Automated footwear manufacturing line and method of operating such manufacturing line

ABSTRACT

A method of manufacturing at least a part of a footwear in an automatic manufacturing line includes providing a footwear part in the form of a leather base layer, providing a footwear part in the form of a leather attachment layer, automatically stacking the leather base layer and the leather attachment layer against each other with an intermediate application of adhesive between them, automatically activating the adhesive, automatically forcing the leather base layer and the leather attachment layer against each other under a pressure with the adhesive between them, curing the adhesive and thereby bonding the leather base layer and the leather attachment layer to each other thereby providing at least a part of a footwear upper.

The invention relates to a method of operating an automated footwear manufacturing line according to claim 1 and an automated footwear manufacturing line according to claim 56.

BACKGROUND OF THE INVENTION

When designing and manufacturing leather-based footwear such as shoes, it is well-known that the manufacturing and the possible designs of such footwear deviates significantly from footwear made from e.g. textiles. The opportunities are different, and the challenges are different. This has the impact that footwear manufacturing lines in real-life systems are highly dependent on human skills both in the sense productivity and quality. The present invention addresses the above problems in different aspects.

SUMMARY

The invention relates to a method of manufacturing at least a part of a footwear in an automatic footwear manufacturing line comprising the steps of

-   -   providing a footwear part in the form of a leather base layer         (LBL),     -   providing a footwear part in the form of a leather attachment         layer (LAL),     -   automatically stacking the leather base layer (LBL) and the         leather attachment layer (LAL) against each other with an         intermediate application of adhesive (A) between them,     -   automatically activating the applied adhesive (A),     -   automatically forcing the leather base layer (LBL) and the         leather attachment layer (LAL) against each other under a         pressure P with the adhesive (A) between them,

curing the adhesive and thereby bonding the leather base layer (LBL) and the leather attachment layer (LAL) to each other thereby providing at least a part of a footwear upper.

The automatic manufacturing line within the scope of the invention is applied for the purpose of implementing a plurality of manufacturing sequences, each manufacturing sequence including the process of assembling footwear parts into a final footwear item or at least an intermediate footwear product including at least a part of a footwear upper preferably including at least a vamp and/or a quarter attached with at least a further footwear upper part.

The automatic manufacturing line includes at least one processing unit and a communication network controlling the operation of an automated stacking arrangement, e.g. a pick and place device in the form of a robot, the operation of activating the applied adhesive and automatically forcing the layers together during at least a part of the curing phase. Moreover, it may be set up as an automatic process is adapted to automatically ensure that optionally required cooling, passively or actively provided, is controlled to ensure that the relevant layers are mutually attached and cured enough to safely pass them on into a next step/station of the manufacturing process.

This next step may e.g. be automatic or manual stitching of the bonded footwear parts into a 3D upper, a subsequent automatic cementing or DIP process for the purpose of gathering/attaching the footwear upper to a sole, a subsequent cutting of superfluous sole material, automatic polishing of the footwear, etc.

It should be noted that the execution of the above part of a manufacturing sequence is highly beneficial to a footwear manufacturing line compared to a conventional process as these steps may provide agility and dynamics to a footwear manufacturing line to a degree never seen before. Different designs and different sizes of a footwear upper may now be manufactured completely automated with no or little human interaction. This is basically impossible or very difficult when attaching parts of a footwear upper according to conventional wisdom in conventional manufacturing systems unless this is performed manually.

In an embodiment of the invention, the method of manufacturing a footwear in an automatic manufacturing line establishes a plurality if manufacturing sequences, the manufacturing sequences including the process of assembling the footwear parts into a final footwear or at least a partially assembled footwear upper.

In the above understanding, each manufactured footwear is understood to be manufactured in is respective manufacturing sequence and another other footwear is manufactured in another respective manufacturing sequence.

The manufacturing sequence in the present context is thus including at least the above steps of automatically stacking, automatically curing and forcing the layers together to ensure a proper assembling/gathering of the footwear upper or the part of the footwear upper to be gathered. The step of curing is also preferably performed automatically in the same manufacturing sequence of the footwear item in question but it should be noted that this step, when implemented into a automated manufacturing line, may be regarded automatic even if no active cooling is applied. The manufacturing sequence may thus be performed so as to ensure that the curing is sufficient, actively or passively, before the bonded footwear parts are moved to be subject to subsequent steps of the manufacturing sequence. This is highly beneficial in terms of quality of the bonding as the compliance with predetermined time, temperature and optional pressure conditions may be kept completely in check in an automatic process.

This is even more the case as different footwear layers may be subject to different curing conditions and different configurations of footwear parts to be bonded may require different conditions. The automated implementation of the curing step may thus be differentiated to be performed differently and optimized with respect to different footwear part combinations thereby increasing manufacturing speed and/or ensuring manufacturing quality.

In a preferred embodiment of the invention, the automatically manufacturing part includes at least the part of the manufacturing sequence starting from the stacking of the footwear parts and until the footwear upper comprises at least a vamp and at least one quarter.

In an embodiment of the invention the method of manufacturing at least a part of footwear includes at least one automated further step of automatically stacking, automatically activating and curing a further leather attachment layer onto a leather base layer and a leather attachment layer already bonded to each other.

In an embodiment of the invention the method of manufacturing at least a part of a footwear includes at least the steps of a manufacturing sequence of bonding all footwear parts in the 2D domain prior to gathering the footwear parts into a 3D upper.

The step of gathering the footwear parts into the 3D domain may be performed by a subsequent manual step of stitching e.g. quarters at the back of the footwear parts, but the final part may also be performed with other different automated or semi-automated steps if so desired.

In an embodiment of the invention the method further includes the subsequent step of integrating the bonded leather base layer (LBL) and the leather attachment layer (LAL) as part of a footwear.

The inventive method of making a footwear may have several advantages in different aspects of the invention over prior art footwear manufacturing methods involving the application of leather. The present invention makes it possible to obtain a multilayered structure of leather layers mutually bonded by glue, and the obtained bonding is strong and robust to stress during daily use of the footwear. The bonded leather layers of the footwear has also proven robust to steam treatment necessary when forming the final footwear. The freedom in design is significantly increased as both distinct shoe parts, such as outer counter or toe caps may now be glued to the footwear without stitching. This keeps manufacturing costs down, but it also adds to the overall flexibility of the upper shoe as such. It is also now possible to apply complex leather patterns to the base layer(s), e.g. the vamp of a shoe or a shaft of a boot without stitching.

It should be noted that top grain surface is intended to cover different degrees of finishing, including buffed top grain. It may within the scope of the invention be advantageous to preprocess the top grain surface of the leather base layer prior to gluing as this may facilitate a better bonding between the leather attachment layer and the leather base layer.

A cow/calf hide is an attractive source of hide for the inventive leather layers, as the strength, composition, visual appearance, flexibility and the thickness in the final footwear is attractive. Is should be noted that e.g. the leather attachment layer(s) may e.g. originate from other types of hides. In other words, the origin of the hides/leather may be different for the leather base layer and the leather attachment layer.

An advantage of gluing at least two pieces of leather together is a special and useful appearance and look of the footwear where it is applied.

A further advantage is that the process of gluing leather pieces together is cost effective and energy saving compared to the typically manual costly sewing processes.

Curing, including cooling may preferably be performed in a separate step subsequent to the pressure and activation step.

Curing, when including cooling may preferably be performed in a separate step subsequent to the pressure and heating step, e.g. a combined step, where the hot-melt glue is melted while keeping the stacked leather layers under pressure.

The curing, including cooling, may be passive or active, meaning that the process steps or the machinery may be adapted to actively cool (e.g. where the compression parts are actively able to vary temperature to both heat in the beginning of the process and then subsequently cool at a later stage without moving the leather assembly from the machine.

The curing may advantageously be performed, monitored and controlled in an automated manner, and the curing may also include keeping the bonding leather at ambient conditions in a predetermined time or a dynamically and automatically determined time during the process.

The intended bonding under pressure or the cooling may be performed alternatively and/or may also be performed at different stations as described or indicated below, i.e.

by subjecting the leather assembly to heat and pressure with compression parts having constant heat at the same time at one station and then subsequently move the assembly from the heated compression parts to another station where the assembly is again pressed but under reduced temperature.

In an embodiment of the invention, the method may include the step of activating the adhesive (A) and then forcing the leather base layer (LBL) and the leather attachment layer (LAL) against each other under a pressure P.

In an embodiment of the invention, the method may include the step of forcing the leather base layer (LBL) and the leather attachment layer (LAL) against each other under a pressure P with the adhesive (A) between them while activating the adhesive (A),

In an embodiment of the invention, the process of curing the adhesive is performed while forcing the leather base layer (LBL) and the leather attachment layer (LAL) against each other under pressure P with the adhesive (A) between.

In an embodiment of the invention, the process of curing involves cooling the adhesive (A) thereby bonding the leather base layer (LBL) and the leather attachment layer (LAL) to each other.

The cooling process may be active or passive, e.g. obtained through ambient cooling. It is however noted that the automated and preferred embodiment of the invention implies that the cooling process, even if the adhesive is merely subjected to ambient conditions, involves that the duration of the cooling process is automatically monitored and used as a control parameter for a correct and optimized curing process in an inline or other types of manufacturing systems.

In an embodiment of the invention, the method of manufacturing a footwear may include activating the applied adhesive (A) by subjecting the adhesive to heat.

The application of heat as a means for activation of heat is somewhat surprising, in particular in an industrial process, in particular when the adhesive has to be activated by heat transmitted to the adhesive through at least one of the leather layers. It should be noted that activation by heat applied when the two leather layers are forced together will very likely invoke shrinkage of the leather but is has proven possible to forecast the degree of shrinkage, even during consideration of two different layers, and very likely different shrinkage.

The activation, also referred to a curing, may e.g. by obtained by thermo curing, radiation curing, curing obtained through chemical activation, electro-curing, etc. The use of different types of curing methods are only

The cooling process may be passive or active as long as the necessary and desired bonding can be obtained.

In the present context fixing the leather base layer (LBL) and the leather attachment layer (LAL) against each other with an intermediate application of adhesive (A) between them basically means that the two layers are stacked in such a way that at least a part of the leather layers, i.e. the leather layers that are to be adhered are overlapping and that adhesive is present in at least a part of the overlapping area.

In an embodiment of the invention, the applied adhesive (A) is activated by subjecting the adhesive to UV-radiation (UV: Ultra violet radiation), IR (IR: Infrared radiation), Ultrasound or any combination thereof.

Activation of adhesive, e.g. by means of UV radiation, facilitates an activation which may be applied in a much more targeted and may therefore be applicable for selective activation e.g. of the adhesive without subjecting the leather to heat and thereby shrinkage.

In an embodiment of the invention, the subjecting the applied adhesive to heat involves a shrinking of at least one of the leather layers, the leather base layer (LBL) and/or the leather attachment layer (LAL).

In an embodiment of the invention, the subjecting the applied adhesive to heat involves a shrinking of at least one of the leather layers, the leather base layer (LBL) and the leather attachment layer (LAL) and wherein the heating temperature T and the heating time is adapted to shrink the leather layers, the leather base layer (LBL) and/or the leather attachment layer (LAL) to predetermined dimension fitting the footwear.

In an embodiment of the invention said method comprises the step of shrinking at least one of the leather base layer (LBL) and the leather attachment layer (LAL) when heating the adhesive (A).

In an embodiment of the invention heating the adhesive (A) is continued over a period of time and/or heated to a temperature by which at least one of the leather base layer

(LBL) and the leather attachment layer (LAL) will shrink within a predetermined dimension range.

In an embodiment of the invention the adhesive (A) is heated for a predetermined time and/or the adhesive is heated to a predetermined temperature corresponding to a predetermined shrinkage of at least one of the leather base layer (LBL) and the leather attachment layer (LAL).

In an embodiment of the invention the adhesive (A) is heated and/or the temperature the adhesive is heated to is determined according to a shrinkage of at least one of the leather base layer (LBL) and the leather attachment layer (LAL).

It should be noted that the dimensioning of the footwear pieces/parts to be attached to a leather base layer of a footwear, if pre-cut, during manufacture must be cut out of the leather in a size/dimension different from the final dimension of the leather attachment layer when glued to the final footwear. Given this information, the skilled person would be able to select the right leather attachment layer, with the right thickness and adapting the over-dimensioning of the pre-cut part (the pre-cut leather attachment layer) so as to fit to the final intended dimensions.

In an embodiment of the invention, the adhesive is formed of a thermoplastic material.

In an embodiment of the invention, the thermoplastic material is a co-polyamide.

In an embodiment of the invention, the thermoplastic material is a polyurethane.

In an embodiment of the invention, the applied adhesive is a foil prior to bonding.

In an embodiment of the invention, the applied adhesive is a web prior to bonding.

In an embodiment of the invention, the provided bonding is non-reactive.

In an embodiment of the invention, the viscosity of the adhesive is low when the adhesive has a temperature above the Tg (Tg: Glass transition temperature).

In an embodiment of the invention, the melting point of the adhesive is above 97 Celsius degrees, preferably above 100 and most preferably above 105.

In an embodiment of the invention, the heat is subjected to the applied adhesive (A) through the leather base layer (LBL) and/or the leather attachment layer (LAL).

In an embodiment of the invention, the leather base layer (LBL) is glued to the leather attachment layer (LAL) by means of non-reactive glue.

Non-reactive glue includes e.g. hot-melt adhesives including thermo-polymer, polyamide, polyesters, polyurethane, polyolefins etc.

Hot melt glues may consist of one base material with various additives. The composition is usually formulated to have a glass transition temperature (onset of brittleness) and a suitable high melt temperature as well.

In an embodiment of the invention, the non-reactive glue is a hot-melt adhesive having a Tg (Tg: Glass transition temperature) between 100 degrees Celsius and 200 degrees Celsius, such as between 110 degrees Celsius and 200 degrees Celsius, such as between 120 degrees Celsius and 200 degrees Celsius, such as between 100 degrees Celsius and 180 degrees Celsius, such as between 100 degrees Celsius and 170 degrees Celsius.

An advantage of applying heat to the process is that it is possible to control the adherence of adhesive to leather. The temperature is raised as the adhesive most preferably is applied to the leather as e.g. a web and needs to be heated in order to melt and mediate a strong binding of the leather pieces.

A further important advantage of applying high temperatures during the adhesion process is that the adhesion will keep its strong binding thorough out the following steps of finishing a footwear. These steps may include e.g. re-heating steps e.g. steaming.

In an embodiment of the invention, the pressure P is at least 2 bars, such as at least 3 bars, such as at least 4 bars.

In an embodiment of the invention, the duration of the heating step is at least 15 sec., such as at least 20 sec., such as at least 25 sec., such as at least 30 sec.

An advantage of applying heat to the process is that it is possible to control the adherence of adhesive to leather. The temperature is raised as the adhesive most preferably is applied to the leather as a foil or web and needs to be heated in order to melt and mediate a strong binding of the leather pieces.

An advantage of applying pressure to the leather during heating of the leather is that the temperature of the leather may be lower than if not applying pressure. The lower temperature is an advantage as the leather may not be burned and it will further keep the leather in the right shape with a minimum of shrinkage. If the temperature is too high, the leather may lose its moisture and therefore turn hard and wavy and thereby loose the flexibility and softness of the leather.

It should also be noted that the heating time must be kept below a maximum where the heating may damage or change the leather layer properties.

In an embodiment of the invention, the leather base layer (LBL) is formed of top grain leather, wherein the top-grain side is facing towards the leather attachment layer (LAL).

In an embodiment of the invention, the leather attachment layer (LAL) is formed of top-grain leather, having the flesh-side facing the towards the leather base layer (LBL)

In an embodiment of the invention, the leather attachment layer (LAL) is formed of top-grain leather, having the top-grain side facing the towards the leather base layer (LBL)

In an embodiment of the invention, the top-grain side of the leather attachment layer (LAL) and/or the leather base layer (LBL) is buffed.

In an embodiment of the invention, the leather attachment layer (LAL) is formed of top-grain leather, having the top-grain side facing towards the exterior of the footwear.

In an embodiment of the invention, the leather attachment layer (LAL) has a thickness of less than 1.4 mm, such as less than 1.2 mm, such as less than 1.0 mm, such as less than 0.9 mm.

In an embodiment of the invention, the leather attachment layer (LAL) has a thickness of less than 1.4 mm, such as less than 1.2 mm, such as less than 1.0 mm, such as less than 0.9 mm and wherein the leather attachment layer (LAL) is a top grain leather.

When reducing the thickness of a top grain leather from the flesh-side, to the above or below indicated thicknesses, the leather attachment layer will get an improved and well-ordered flesh-side of the top grain leather. This also means that the distribution of fibres at the top grain leather gradually is becoming more uniform and closer to the top-grain distribution thereby facilitating glue bonding to the flesh-side of the leather attachment layer. Other mechanisms may be drivers for the improved bonding experienced and facilitated by the reduced thickness of the leather attachment layer.

In an embodiment of the invention, the thickness of the leather attachment layer (LAL) is between 0.3 mm to 2.0 mm, such as between 0.5 mm to 2.0 mm, such as between 0.5 mm to 1.5 mm, such as between 0.7 mm to 1.3 mm.

In an embodiment of the invention, the thickness of the leather attachment layer (LAL) is between 0.3 mm to 2.0 mm, such as between 0.5 mm to 2.0 mm, such as between 0.5 mm to 1.5 mm, such as between 0.7 mm to 1.3 mm and wherein the leather base layer (LBL) and the leather attachment layer (LAL) is formed on the basis of cow hide.

In an embodiment of the invention, the thickness of two adhered leather layers (LBL, LAL) is between 0.5 mm and 4 mm, such as between 0.7 to 3.5 mm, such as 0.9 mm to 3.3 mm, such as 1.0 mm to 3 mm, such as 1.3 mm to 2.8 mm, such as 1.5 mm to 2.5 mm, such as 1.2 mm to 2.2 mm, such as 1.0 to 2.0 mm, such as 0.8 to 1.8 mm.

In an embodiment of the invention, the leather attachment layer (LAL) is thinner than the leather base layer (LBL).

The thickness of a leather layer may e.g. be measured by a SATRA STD 483 “Thickness gauge for leather”

In an embodiment of the invention, the leather base layer (LBL) is forming at least part of a leather quarter of a footwear.

In an embodiment of the invention, the leather base layer (LBL) is forming at least part of a leather vamp of a footwear.

In an embodiment of the invention, the leather attachment layer (LAL) is forming at least part of a leather counter of a footwear.

In an embodiment of the invention, the leather attachment layer (LAL) is forming part of a leather toe cap of a footwear.

In an embodiment of the invention, the leather attachment layer (LAL) is a pattern defining part of the shoe facing towards the exterior, preferably bonded to the vamp and/or a quarter of a shoe.

In an embodiment of the invention, the leather attachment layer (LAL) is a plurality of pattern defining parts of the shoe facing towards the exterior, preferably bonded to the vamp and/or a quarter of a shoe.

In an embodiment of the invention, the lamination comprises a temperature of at least 170 Celsius degrees.

In an embodiment of the invention, the attachment forces between the leather base layer (LBL) and the leather attachment layer (LAL) is at least 5 kN/m, more typically above 10 kN/m, or even above 15 kN/m.

In an embodiment of the invention, the attachment forces between the leather base layer (LBL) and the leather attachment layer (LAL) is at least 5 kN/m, more typically above 10 kN/m, or even above 15 kN/m when measured according to ISO 3376: 2011.

The attachment forces, the ultimate tensile strength expressed in kN/m is the pulling force required to break a 1 m wide sample of the material. A suitable test for measuring the ultimate tensile strength of the reinforcing fabric is ISO 3376:2011. An alternative test specifically adapted for testing tensile properties of polymer matrix composites which could be used is ASTM D3039.

In an embodiment of the invention, leather layers comprising a laminated base layer (LBL) glued to a leather attachment layer (LAL) has a water vapor permeability of above 5 mg/cm2/hour, such as above 8 mg/cm2/hour, such as above 10 mg/cm2/hour and wherein the breathability is measured according to SATRA TM 172.

In an embodiment of the invention, the variation of breathability of the leather layers varies with less than 25% measured over plurality of leather layers.

An important advantage of using adhesive in the form of e.g. a foil or web compared to e.g. a spread glue or a spread hot melted glue is a that the water vapor permeability/breathability of the leather may be obtained. A further advantage is less variation of the breathability of the leather throughout the treated leather pieces.

A further advantage of using an adhesive web is that the softness of the leather is kept even after an adhesive is applied. Other types of glue often result in hardness of the product after it has been pasted. It is therefore highly important to optimize and choose the right adhesive.

In an embodiment of the invention, the method is performed by in an automatic footwear processing arrangement (AFPA) having an input (I) and an output (0), wherein the method of providing the leather base layer (LBL) and the leather attachment layer (LAL) is performed in an automatic process transporting the leather base layer (LBL) and the leather attachment layer (LAL) from the input (I) and automatically stacking these, one layer at least partially overlapping the other layer and wherein the activation is performed automatically by means of an automatic adhesive activation arrangement (AAA) and wherein the process of forcing the leather base layer (LBL) and the leather attachment layer (LAL) against each other under a pressure P with the adhesive between them is performed by an automatic pressure activation arrangement (APA).

In an embodiment of the invention, the process of curing the adhesive (A) is performed subsequent to activation by means of an automatic curing arrangement (ACA).

In an embodiment of the invention, the process of curing the adhesive (A) is performed subsequent to activation by means of an automatic cooling arrangement (ACOA).

In an embodiment of the invention, the adhesive to be activated is pre-adhered to the leather base layer (LBL) and/or the leather attachment layer (LAL)

In an embodiment of the invention, two or more input footwear parts, i.e. at least a leather base layer LBL and a leather attachment layer LAL are automatically stacked to be at least partly overlapping by an automatic stacking arrangement (ASA).

In an embodiment of the invention, footwear parts, i.e. at least a leather base layer LBL and a leather attachment layer LAL, are automatically cleaned/removal of dust/preprocessed prior to reactivation of adhesive already present on the leather footwear parts and/or prior to the application of adhesive to the footwear parts by means of a pre-adhesion processing arrangement (PAPA)

In an embodiment of the invention, the leather base layer (LBL) and/or the leather attachment layer (LAL) are automatically provided by a leather cutting arrangement (LCA).

In an embodiment of the invention, the leather footwear part comprising a leather layer having a top-grain side and a flesh side, the flesh side or the top-grain side comprising an adhesive bonded to the pre-glued leather part by hot-melting.

In an embodiment of the invention, the thickness of the leather footwear part is below 1.5 mm, such as below 1.2 mm.

In an embodiment of the invention, the thickness of the leather footwear part is within the range of 0.3 mm to 1.5 mm.

In an embodiment of the invention, the pre-glued leather footwear part at the glue-side is attached temporarily to a paper, a sheet or a foil.

When attaching the glue side of the pre-glued leather footwear part, it is possible to obtain a leather part which is ready for use in a footwear manufacturing line with a reduced risk of contamination of the glue-side of the pre-glued footwear leather part.

The paper or the foil is advantageously treated with a non-stick compound to ensure a peel-off immediately prior to adhering the leather footwear part to another leather layer, such as a vamp or a quarter.

In an embodiment of the invention, a footwear comprising a footwear upper (FU) attached to a sole (S), the footwear upper comprising

-   -   at least one leather base layer (LBL) and     -   at least one leather attachment layer (LAL),

wherein the leather base layer (LBL) is glued to the leather attachment layer (LAL) with a hot-melt thermoplastic adhesive.

In an embodiment of the invention, a footwear according to claim 56 comprising a footwear upper (FU) attached to a sole (S), the footwear upper comprising

-   -   at least one leather base layer (LBL) having a base layer top         grain surface and     -   at least one leather attachment layer (LAL) having an attachment         top grain surface and a flesh-side surface,

wherein the leather base layer (LBL) is glued to the leather attachment layer (LAL) with the base layer top grain surface facing the flesh-side of the leather attachment layer (LAL).

In an embodiment of the invention, a footwear according to claim 56 or 57 and wherein the footwear is manufactured according to any of the claims 1-55.

According to a further aspect, the invention relates to an automatic footwear processing arrangement (AFPA) having an input (I) and an output (0), wherein the method of providing the leather base layer (LBL) and the leather attachment layer (LAL) is performed in an automatic process transporting the leather base layer (LBL) and the leather attachment layer (LAL) from the input (I) and stacking these, one layer at least partially overlapping the other layer and wherein the activation is performed automatically by means of an automatic adhesive activation arrangement (AAA) and wherein the process of forcing the leather base layer (LBL) and the leather attachment layer (LAL) against each other under a pressure P with the adhesive between them is performed by an automatic pressure activation arrangement (APA).

It should be noted that the inventive manufacturing method includes the option of adhering as many parts of the footwear as possible and then e.g. supplementing with relatively few stitches in relation to some or a few of footwear parts. It should be noted that a relatively limited stitching may easily be applied within an automated manufacturing robot line as long as comprehensive and long continuous stitching is avoided or kept at a very low level.

It should be noted, although conventional stitching may advantageously be avoided within the scope of the invention, that the adhesion process in itself may be very advantageous as footwear-designs previously limited by the ability of conventional stitching setups, may now be made in an automated manner.

An automatic arrangement in the present context is e.g. referring to a unit or a number of automatically operated units working automatically at least between an input and an output of the arrangement. The transfer to the input(s) and from the output(s) may thus be implemented as manual, semi-automatic or automatic processes.

In an embodiment of the invention, the process of curing the adhesive (A) is performed subsequent to activation by means of an automatic curing arrangement (ACA).

In an embodiment of the invention, the process of curing the adhesive (A) is performed subsequent to activation by means of an automatic cooling arrangement (ACOA).

In an embodiment of the invention, the adhesive to be activated is pre-adhered to the leather base layer (LBL) and/or the leather attachment layer (LAL)

In an embodiment of the invention, two or more input footwear parts, i.e. at least a leather base layer LBL and a leather attachment layer LAL are automatically stacked to be at least partly overlapping by an automatic stacking arrangement (ASA).

In an embodiment of the invention, footwear parts, i.e. at least a leather base layer LBL and a leather attachment layer LAL, are automatically cleaned/removal of dust/preprocessed prior to reactivation of adhesive already present on the leather footwear parts and/or prior to the application of adhesive to the footwear parts by means of a pre-adhesion processing arrangement (PAPA).

In an embodiment of the invention, the leather base layer (LBL) and/or the leather attachment layer (LAL) are automatically provided by a leather cutting arrangement (LCA).

In an embodiment of the invention, the automatic footwear processing arrangement is operated according to any of the claims 1-51.

In an embodiment of the invention, the leather of the leather base layer/leather attachment layer comprises tanning agents in the amount of 3 to 15% by weight of the leather.

In an embodiment of the invention, the leather base layer/leather attachment layer comprises tanning agents in the amount of 7 to 15% by weight of the leather and wherein the tanning agents are vegetable tanning agents.

In an embodiment of the invention, the vegetable tanning agents are obtained from chestnut wood, quebracho wood, tara pods, catechu, chinese gallnut, turkish gallnut, gambier, myrobalan, oakwook, sumac, bark from yate and/or valonia oak.

In an embodiment of the invention, the leather of the leather base layer/leather attachment layer comprises tanning agents in the amount of 3 to 12% by weight of the leather and wherein the tanning agents includes chrome tanning agents.

In an embodiment of the invention, the chrome tanning agents includes chromium, chromium salts and/or derivatives thereof.

In an embodiment of the invention, the leather base layer/leather attachment layer comprises chrome tanning agent(s) in the amount of 1 to 7% by weight of the leather, such as 2 to 6% by weight of the leather such as 2 to 5% by weight of the leather.

The specific content of chrome tanning in the amount of 1 to 7% by weight of the leather, such as 2 to 5% by weight of the leather is in particular attractive in relation to the inventive binding between two leather layers as this content of chrome in the leather of the bonded layers makes is possible to use heat-activated adhesive to attach the leather to the reinforcing fabric. It is moreover, and even more advantageous in applications where the leather has to be steamed e.g. for purposes of shaping etc.

In an embodiment of the invention, the chrome tanning agents includes chromium, chromium salts and/or derivatives thereof.

In an embodiment of the invention, the base layer top grain surface has been buffed.

In an embodiment of the invention, the leather base layer (LBL) and the leather attachment layer (LAL) comprises between 1 to 15% by weight of fatliquoring, such as between 1 to 10% by weight of fatliquoring.

In an embodiment of the invention, the base layer top grain surface comprises less than 5% by weight of fat, such as less than 4% by weight of fat, such as less than 3 by weight of fat.

Moreover, the invention relates to an automatic footwear processing arrangement (AFPA) defining an automatic footwear manufacturing line having an input (I) and an output (O), the footwear manufacturing line including one or more stations configured for performed process steps, wherein the arrangement includes a station (STA) in the form of at least one automatically operated stacking arrangement, such as a pick-and-place device (PAPD), stacking a leather base layer (LBL) and a leather attachment layer (LAL) obtained from the input (I), one layer at least partially overlapping the other layer and wherein the pick-and place device is cooperating with an associated automatic adhesive activation arrangement (AAA), the adhesive activation arrangement being arranged to automatically activate an adhesive between a mutually stacked leather base layer (LBL) and leather attachment layer (LAL), the adhesive activation arrangement including or cooperating with an automatic pressure activation arrangement (APA) configured to force the leather base layer (LBL) and the leather attachment layer (LAL) against each other under a pressure P with the adhesive between them at the same time or subsequent to adhesive activation performed by the adhesive activation arrangement.

The footwear processing arrangement may also be referred to as a footwear manufacturing line.

Is should that pressure may be temporarily or permanently released after a predetermined time, enough to ensure a proper bonding between the layers. However, it should also be noted that pressure may also be released temporarily when moving the stacked and bonded layers from the activation and/or pressure arrangement to a subsequent process. This may e.g. be performed if the bonding is sufficient to ensure the above said moving but also when it is preferred to reestablish pressure when moving the bonded layers further on in the manufacturing line.

In an embodiment of the invention the stations of the manufacturing line is interconnected with a transporting arrangement (TA) automatically configured for transporting footwear parts from one station to another and wherein the transportation of the footwear parts from station to station are controlled at least partly by a control arrangement (CA) so as to establish a manufacturing sequence for respective footwear items.

It should be noted that the control arrangement may be directly communicating with the individual stations of the manufacturing line both for ensuring that the footwear parts or bonded footwear parts are transported correctly between the stations but also optionally also supervising the individual footwear parts or gradually partly gathered upper throughout the process.

It should also be noted that the transporting arrangement may be implemented by a conveyer, drones, whatever suitable transportation means known by the skilled person.

It should also be noted that he central control arrangement may automatically receive data from the different stations and thereby track and log footwear parts or partly manufactured footwear upper during the manufacturing process.

In an embodiment of the invention the control arrangement is monitoring the movement of the partially gathered footwear upper parts throughout a manufacturing sequence of a footwear upper.

In an embodiment of the invention the control arrangement is monitoring the movement of the partially gathered footwear upper parts throughout a manufacturing sequence of a footwear upper and also monitors which footwear uppers are manufactured at which stations.

In an embodiment of the invention the process of curing the adhesive (A) is performed subsequent to activation by means of an automatic curing arrangement (ACA).

In an embodiment of the invention the process of curing the adhesive (A) is performed subsequent to activation by means of an automatic cooling arrangement (ACOA).

In an embodiment of the invention the adhesive to be activated is pre-adhered to the leather base layer (LBL) and/or the leather attachment layer (LAL)

In an embodiment of the invention two or more input footwear parts, i.e. at least a leather base layer LBL and a leather attachment layer LAL are automatically stacked to be at least partly overlapping by an automatic stacking arrangement (ASA).

In an embodiment of the invention footwear parts, i.e. at least a leather base layer LBL and a leather attachment layer LAL, are automatically cleansed prior to reactivation of adhesive already present on the leather footwear parts and/or prior to the application of adhesive to the footwear parts by means of a pre-adhesion processing arrangement (PAPA)

In an embodiment of the invention the leather base layer (LBL) and/or the leather attachment layer (LAL) are automatically provided by a leather cutting arrangement (LCA).

In an embodiment of the invention the automatic footwear processing arrangement includes at least one visual detection system configured for checking footwear parts of bonded footwear parts up against preconfigured references or pre-taught algorithms to ensure that relevant process steps are functioning according to expectation.

In a preferred embodiment such a visual detection system is designed and configured for monitoring shrinkage of leather footwear parts subsequent to the activation of adhesive.

In an embodiment of the invention the automatic footwear processing arrangement includes at least one displacement device interacting with the manufacturing line, and wherein the displacement device is configured to automatically removing footwear parts of bonded footwear parts from the manufacturing line if footwear parts does not satisfy a manufacturing criteria stored in the control arrangement (CA) controlling the manufacturing line, and wherein the displacement device communicates that such a displacement has been performed to the control arrangement (CA).

In an embodiment of the invention the automatic footwear processing arrangement further includes an automatic stitching arrangement configured to performed supplementary stitching subsequent to the stacking and bonding of at least the leather base layer (LBL) and the leather attachment layer (LAL).

In an embodiment of the invention the manufacturing line includes a subsequent automatic sole attachment arrangement for cementing a sole to the footwear upper.

In an embodiment of the invention the manufacturing line includes a subsequent automatic arrangement configured for direct injection of a sole to the footwear upper.

In an embodiment of the invention an automatic footwear processing arrangement according to any of the preceding claims 56-70 is implemented according to the method of any of the claims 1-55.

THE FIGURES

The invention will be described in the following with reference to the drawings, where

FIGS. 1A and 1B illustrate some principle parts of a footwear within the scope of the invention,

FIG. 2 illustrates a backpiece and cross-section of a backpiece made within the scope of the invention,

FIG. 3 illustrates a vamp and a toe cap and cross-section of a vamp and toe cap made within the scope of the invention,

FIG. 4 illustrates a vamp and a tongue made within the scope of the invention,

FIG. 5 illustrates a method of adhering or laminating an adhesive to a piece of leather made within the scope of the invention,

FIG. 6 illustrates another method of adhering or laminating an adhesive to a piece of leather made within the scope of the invention,

FIG. 7 illustrates a method of fixation of an adhesive to a piece of leather made within the scope of the invention,

FIG. 8 illustrates a method of applying pressure made within the scope of the invention,

FIG. 9 illustrates an automatic footwear processing arrangement and different stations to be applied within such as system,

FIG. 10 a-c illustrate different embodiments of footwear processing equipment within the scope of the invention,

FIG. 11 a-d illustrate various arrangements and devices for footwear processing and production according to embodiments of the invention,

FIG. 12 a-d illustrate additional various arrangements and devices for footwear processing and production according to embodiments of the invention,

FIG. 13 illustrates a further various arrangements and devices for footwear processing and production according to embodiments of the invention,

FIG. 14 a-d illustrate a robot and different kinds of robot tools for footwear processing according to embodiments of the invention,

FIG. 15 a-c illustrate attachment of footwear parts to a fixture according to embodiments of the invention,

FIG. 16 a-c illustrate placement of footwear parts on a production tray according to embodiments of the invention,

FIG. 17 a-c illustrate various adhesive activation arrangements according to embodiments of the invention,

FIG. 18 a-e illustrate exemplary steps of applying an adhesive activation arrangement to footwear parts according to embodiments of the invention,

FIG. 19 illustrates another automated footwear processing arrangement according to embodiments of the invention,

FIG. 20 illustrates yet another automated footwear processing arrangement according to embodiments of the invention and where

FIG. 21 illustrates a manufacturing line according to an embodiment of the invention.

DETAILED DESCRIPTION

In terms of terminology, top grain surface is the upper portion or outer covering of the animal whereas split is the under layer which is removed by splitting operation in the leather making/tanning process.

Full grain refers to top grain leather where no sanding of the surface takes place. This leaves the original surface texture visible in the final leather, including hair follicles and any natural scar tissue or other skin defects. Additionally, any natural defects in the hide remain in the final piece, which can create natural lines of weakness that render the leather difficult to use in certain applications. For instance, in applications such as shoes, the natural weaknesses may cause the leather to preferentially bend in the wrong place, making the shoe uncomfortable during use.

Nubuck leathers have the surface layer removed or modified typically by a buffing process. Although the leather still has the pronounced network of natural fibres and corium structure giving the leather strength, the very top grain surface is effectively removed.

The buffing process used to form nubuck leathers leaves protein fibres that produce a velvet-like feel. Artificially embossing nubuck leather can create a surface texture, but often the embossing step damages the protein fibres and undermines the velvet-like feel.

Split leather is created from the fibrous part of the hide left once the top-grain has been separated from the hide, e.g. to be used as full grain or top grain leather. Split grain leather may have reduced strength as compared to comparable thicknesses of top grain leather, as the fibres tend to be more aligned. To compensate for this, split leather may need to be reinforced prior to use. Any grain texture is furthermore embossed on to the final leather.

Only full grain leathers maintain the natural grain and inherent strength of the original hide. When the sample thickness of full grain leather is reduced, the strength drops dramatically rendering them unsuitable for certain uses. Corrected grain and split leathers lack a natural grain. In order to attain a high quality appearance of natural full grain leather, they typically have an artificial grain embossed onto their surface.

Whereas automated assembly lines and robot featuring assembly lines are well-known within numerous different types of industries, this is rarely seen within the footwear industry and when it is applied, it is used for very specific, insignificant and isolated stations of a complete manufacturing process.

FIG. 21 illustrates a footwear manufacturing line ML according to an embodiment of the invention.

The footwear manufacturing line ML may also be referred to as an automatic footwear processing arrangement AFPA for bonding of footwear parts FP. The manufacturing line has an input I and an output O, the footwear manufacturing line including one or more stations configured for performing manufacturing sequence process steps.

The stations are operatively connected by means of a transporting arrangement TA, here in the form of a conveyor. Other types of transporting arrangements may be applied within the scope of the invention.

The manufacturing line includes a station STA in the form of at least one automatically stacking arrangement ASA, e.g. implemented as an automatic pick-and-place device stacking a leather base layer and a leather attachment layer obtained from the input I, one layer at least partially overlapping the other layer and wherein the pick-and place device is cooperating with an associated automatic adhesive activation arrangement AAA. The illustrated footwear parts is intended to show e.g. the footwear parts as explained in relation FIG. 2A as feed to and by the input and stacked into the stacked footwear parts of FIG. 2C. The illustrated footwear parts are stacked by the automatic stacking arrangement ASA but they are not yet bonded to each other. The illustrated footwear parts are illustrated for the purpose of showing examples, not for the purpose of restricting the invention to the specific footwear parts, unless otherwise noted.

The adhesive activation arrangement is arranged to automatically receive a mutually stacked leather base layer and a leather attachment layer from the automatic stacking arrangement and activate an adhesive between the stacked leather base and the leather attachment layer. In the illustrated embodiment, the footwear parts have been pre-adhered prior to being fed to the input. Application of adhesive or cementing may of course be performed in the manufacturing line if so desired, but this would require that a station is configured for applying adhesive to the footwear parts in the desired pattern, preferably prior to or at least at latest during stacking of the relevant footwear parts.

The adhesive activation arrangement including or cooperating with an automatic pressure activation arrangement APA configured to force the leather base layer LBL and the leather attachment layer LAL against each other under a predefined pressure with the adhesive between them at the same time as activating the adhesive. This means that the illustrated adhesive activation arrangement is configured for both putting pressure to the stacked footwear parts and activating the adhesive at the same time. In principle, the pressurizing may be performed at a subsequent station as long as the duration of time until such re-pressure is performed is relatively low so as to ensure a proper bonding and it is also necessary to ensure that the stacked footwear parts are not mutually displaced during this critical time.

The illustrated footwear parts are stacked on a production tray PT. In the present embodiment the production tray serves to transport the footwear parts between the stations but also to facilitate a transport between stations where the proper stacking is maintained even before the final desired bonding is obtained by curing.

Further down the line, the manufacturing line includes a station in the form of an automatic curing arrangement ACA. In the present embodiment, the curing arrangement is applied for cooling the stacked footwear parts after the adhesive between them has been activated so as to ensure a proper bonding. This part of the process is crucial but extremely attractive for automatic implementation as the duration of curing time, and the cooling may be complete adapted and optimized to even the individual footwear parts and stacks.

Finally, the manufacturing line includes an optional visual detection system VDS applied for the purpose of checking whether the processing has been performed according to expectation. Further stations may be applied in a manufacturing line according to the invention and the manufacturing line may be configured differently. Different configurations are illustrated and explained below.

The transportation of the footwear parts from station to station is controlled at least partly by a control arrangement CA so as to establish a manufacturing sequence for respective footwear items.

It should be noted that the control arrangement may be directly communicating with the individual stations of the manufacturing line both for ensuring that the footwear parts or bonded footwear parts are transported correctly between the stations but also optionally also supervising the progression of the manufacturing sequences of a plurality of individual footwear parts, footwear items or footwear uppers gradually and/or partly gathered uppers.

The process of receiving footwear parts at the input of the manufacturing line, moving these along, optionally with further added footwear parts along the line, attaching these to another and finally obtaining at least a part of a footwear upper, e.g. at least a complete 2D upper, may be referred to as a manufacturing sequence. The output of the manufacturing sequence may thus be partially completed footwear uppers, complete footwear uppers or even footwear including cemented or DIP′ed soles (DIP: Direct injection process)

It should also be noted that each station may comprise an individual control unit (not shown) and may include both software suitable for obtaining the desired functionality of the individual station but also to ensure a proper communication with the control arrangement CA.

To understand and appreciate the automated manufacturing line in the present context it is necessary to understand some fundamental physics and mechanical realities. These are to be explained below in order to facilitate understanding of the present automated footwear manufacturing line.

Thus, in order to explain the central features and understanding of the adhering of footwear leather parts of the invention, FIG. 1-8 illustrate different ways of organizing and implementing a proper bonding of leather footwear parts, in particular of footwear uppers, without compromising the footwear design, ensuring a proper and intended footwear size and ensuring that the leather texture is as it is intended in the final footwear upper.

FIGS. 9 to 20 goes on in explaining automatic implementations within the scope of the invention.

FIG. 1 illustrates an exemplary footwear which may be made within the scope of the invention.

The exemplified footwear is a shoe 100. The illustrated shoe 100 comprises an upper part UP comprising a front part (FP) and back part (BP). The front part comprises footwear defining parts such as a vamp 101 and tongue 102, two quarters 103 and a toe cap 104.

The illustrated shoe 100 comprises a backpiece BP. The backpiece comprises footwear defining parts such as an outer counter 106, eyelets 107, and facing 108.

The illustrated shoe 100 may preferably comprise a lining on the inner side of the quarter. For illustrative purposes the lining is not shown.

The illustrated backpiece BP may comprise stitches to facilitate a curvature of the backpiece. The stitches are not illustrated on the figure.

The front part FP and backpiece BP are attached to each other where the backpiece BP is overlapping the front part FP. The attachment of the two parts FP to the BP may be facilitated e.g. by adhesion facilitated with conventional glue or other adhesives suitable for adhering the two pieces. The attachment of the two parts FP to the BP may also, either alone or in combination with adhesives, be facilitated with stitching.

The upper part UP is attached to a sole S e.g. by adhesion, gluing, stitching, injection molding or any relevant methods of attaching a sole. The attachment of the upper part UP to the sole may be done before or after the two pieces of front part FP and backpieces BP are attached to each other.

The sole may comprise several parts and layers (not shown).

The shoe may of course comprise other not-shown features and parts and the shapes and configuration of the parts may be different. Most shoes comprise more than 15 or 20 shoe defining parts.

FIG. 1B illustrates an alternative footwear within the scope of the invention in the form of a boot comprising, in simple terms, a vamp 1010 and a shaft 1030. Multiple distinct leather pieces 1040 has been bonded to the vamp 1010 and the shaft 1030 by means of glue. The vamp 1010 and the shaft 1030 is forming a leather base layer and the leather pieces 1040 forms a number of leather attachment layers bonded to the leather base layer(s) with little or no stitching

FIG. 2A illustrates a top view of parts of a backpiece e.g. of the shoe of FIG. 1 , comprising an outer counter 202, two quarter pieces 201A and 201B and two facing pieces 202A and 202B.

FIG. 2B illustrates cross-sections of the parts of a backpiece illustrated in FIG. 2A the transverse direction, i.e. cross sections of the outer counter 202, two quarter pieces 201A and 201B and two facing pieces 202A and 202B.

FIG. 2C illustrates a top view of an assembled backpiece e.g. of the backpieces illustrated in FIG. 2A, comprising an outer counter 202, two quarter pieces 201A and 201B and two facing pieces 202A and 202B. The two quarter pieces thereby forming a leather base layer (LBL) and the outer counter and the two facing pieces thereby forming a leather attachment layers (LAL). The assembly of the pieces may be facilitated by a preliminary or permanent adhering of the pieces together e.g. by adhesive.

FIG. 2D illustrate a cross-section of the assembled backpiece as illustrated in FIG. 2C as illustrated in the transverse direction. The back piece comprises an outer counter 202, two quarter pieces 201A and 201B and two facing pieces 202A and 202B.

The outer counter 202 is bonded to the two quarter pieces 201A and 201B by an adhesive (A) layer 203 and the two facing pieces 202A and 202Bs are connected to the two quarter pieces 201A and 201B by layers of adhesives 203A and 203B respectively.

In the illustrated back-piece provided according to an embodiment of the invention, the two quarter pieces 201A and 201B forms a leather base layer(s) LBL upon which two facing pieces 202A, 202B and the outer counter 202 are bonded by means of glue. The two facing pieces 202A, 202B and the outer counter 202 may elsewhere be referred to as leather attachment layers LAL.

In the presently illustrated embodiment, the leather forming the base layer(s) are top grain leather, buffed or non-buffed, with the top-grain side facing towards the leather attachment layers LAL, the two facing pieces 202A, 202B and the outer counter 202.

The present illustrated leather attachment layers LAL are preferably from top grain leather also, having the flesh-side facing the leather base layer(s) LBL, here the two quarter pieces 201A and 201B and the top grain side facing to the exterior of the final shoe.

Possible adhesives are described elsewhere in the application, but in the present embodiment a co-polyamide has been applied.

The adhesive may be present in a continuous layer or be present as a “perforated” or non-continues adhesive layer facilitating both sufficient bonding but also breathing or some kind of moisture transport through the layers.

FIG. 3A illustrates a top view of parts of an upper e.g. of the shoe of FIG. 1 , comprising a vamp 301 and a toe cap 303 made within the scope of the invention. The two pieces, vamp 301 and toe cap 303 are assembled by fitting the toe cap 303 on top of the vamp 301 as illustrated and then attached together by adhesive (A). The vamp thereby forms a leather base layer (LBL) and the toe cap forms a leather attachment layer (LAL).

FIG. 3B illustrates a cross-section of the above parts of an upper e.g. of the shoe of FIG. 1 illustrated in a transverse direction of a vamp 301 and toe cap 303. The toe cap 303 is connected to a layer of adhesive 302 and then connected to the vamp 301.

FIG. 4 illustrates a top view of parts of an upper e.g. of the shoe of FIG. 1 , comprising a vamp 401 and tongue 402 made within the scope of the invention.

FIG. 5A illustrates a cross-section of an assembly according to an example of a method for pre-laminating a leather piece 505 e.g. as illustrated in FIG. 2 (202, 202A, 202B) and FIG. 3 (303) with an adhesive as illustrated in FIG. 2 (203, 203A, 203B) and FIG. 3 (302).

FIG. 5A thus shows a leather piece 505, a layer of adhesive, e.g. a web or a foil of non-melted thermoplastic hot-melt adhesive and a Teflon sheet 507.

With reference to FIG. 5A, FIG. 5B illustrates a cross-section of an example of adhering the adhesive 506 to a leather piece 505. The leather piece 505, adhesive 506 and Teflon sheet 507 are subjected to first compression part 501 from one side and a second compression part 502 from the opposite side and application of heat T from at least one side of the compression parts 501 or 502 in combination with pressure P. In the present embodiment, heat is only actively transferred from the first compression part 501.

The application of adhesive to the leather parts may be processed with one leather part at the time but for industrial applications it may be preferably to pre-laminate several pieces of leather in the same process.

The two compression parts 501 and 501 may be parts on a machine e.g. a machine such as a transfer flatbed pressing machine such as a Galaxy Air Double but could also be any other machine or apparatus capable of applying the relevant temperature and pressure.

FIG. 5C illustrates a cross-section of an example of detaching Teflon sheet 507 from the adhesive 506 that is attached to the leather 505.

The Teflon sheet is only slightly attached to the adhesive side of the leather. Immediately after detachment of the Teflon sheet from the adhesive side of the leather, the adhesive is functioning for further procedures such as adhering two pieces of leather together. For industrial applications it may be advantageous to cover the prelaminated leather with a sheet of paper e.g. a heat resistant paper PA that removably adhere and cover the prelaminated leather for optimal transportation of the pieces and for avoidance of contamination.

The detachment of the Teflon sheet may be done manually or could also be an automatized non-manually process.

Subsequently to the prelamination, the leather pieces may be re-cut depending on the subsequent processes and applications.

FIGS. 5D and 5E illustrate a cross-section of an example of adhering a prelaminated leather 505 with adhesive 506 to another piece of leather 508. The prelaminated leather 506 could e.g. be a facing piece 202A and the other piece of leather 508 could e.g. be a quarter piece 201A as illustrated in FIG. 2 .

The adherence of the leather parts may be processed with adhering one leather piece to another leather piece at the time but for industrial applications it may be preferably to adhere several pieces of leather in the same process.

In the process it might be advantageous to use of sheet of paper PA e.g. a heat resistant paper between the leather and compression parts. This is not shown.

The two compression parts 501 and 501 may be parts on a machine e.g. a machine such as a transfer flatbed pressing machine such as a Galaxy Air Double but could also be any other machine or apparatus capable of applying the relevant temperature and pressure.

The leather piece 505, adhesive 506 and leather piece 508 are pressed by a compression part 501 from one side and a compression part 502 from the opposite side and during application of heat T and pressure P from at least one side of the compression parts 501 or 502.

FIG. 5F illustrates a cross-section of an example of cooling the attached leather pieces 505 and 508 by pressing the attached and partly bonded leather pieces to a compression part 503 and 504 to facilitate a cooling process of the leather pieces 505 and 508. The cooling process may be a passive or active process. An example of a machine to facilitate a cooling process could be a reinforcement press machine. The cooling process, active or passive, is important for the strong binding of the leather pieces adhered within the scope of the invention as the leather pieces must be mutually fixed during the cooling.

FIGS. 6A and 6B illustrate a cross-section of an example of adhering two leather pieces 601 and 603 together facilitated by adhesive 602 without prelamination. All three layers; one leather piece 601, an adhesive 602 and another leather piece 603 are fixed mutually and fitted together and subjected to a compression part 501 from one side and a compression part 502 from the opposite side and application of heat T and pressure P from at least one side of the compression parts 501 or 502 to hot-melt the adhesive 602. A subsequent cooling during maintaining of the fixation of the two leather pieces.

An advantage of not using pre-laminated leather could be that it is only necessary to heat the leather once which may be industrial beneficial, but it may also be an advantage in order to avoid shrinkage of the leather and for keeping the softness of the leather.

A following process should preferably include a cooling process e.g. as illustrated in FIG. 5F, but this is not shown here.

FIG. 7 illustrates a cross-section of an initial fixation of an adhesive 702 to a leather piece 701. The adhesive 702 may have been prelaminated to another leather piece 703 prior to the fixation. The adhesive 702 may also not have been laminated to the other piece of leather 703 and instead fixated by the method illustrated for the adhesive 702 and the leather piece 701.

The fixation may be done by using a e.g. welding iron W by dot point welding uniformly around the piece of adhesive 702 to secure adhesive to leather for pre-pressing operation.

The fixation may be done by use of other devises or methods suitable to fix the adhesive 702 to the leather pieces 701 and/or 703.

Other types of pre-fixation, e.g. mechanical or chemical, may be applied within the scope of the invention.

FIG. 8 illustrates an example of applying pressure P to a stack of leather comprising a leather piece 801, adhesive 802, and another leather piece 803 respectively. The stack is illustrated as a cross-section. Applying pressure P to the stack may result in a compression of at least one piece of leather.

Applying pressure to a stack of a leather where the adhesive is in between two leather pieces may result in removal of pockets of air that might be present in the leather. Removal of the air pockets may lead to a greater heat transportation of the leather and therefore less heat may be required to heat up the adhesive through the leather.

The exemplified footwear is a shoe. Other types of footwear may be relevant within the scope of the invention, such as a boot. It should also be noted that shoes may be configured or manufactured in many different ways and be formed of different types of shoe-defining parts but still considered included in the invention as long as principle parts of the shoe, are made according to the provisions of the invention. Further, it should be noted that there may be different nomenclature of the different parts of the shoe e.g. toe cap may also be termed as mud gourd etc. and the exemplary footwear parts, made within the scope of the invention, also includes synonyms of the shoe parts.

The adhesive illustrated in the above description e.g. as 203, 302, 506, 602, 702, and 802 may preferably be applied as an adhesive foil, film, slit film, web, dots, or net with various degrees of openness to ensure optimal bonding and high breathability of the footwear. The pattern of the adhesive is preferably an open, permeable or flexible application

The term prelamination refers to the process of applying an adhesive to a piece of leather and the term lamination refers to applying a piece of leather to the prelaminated leather facing the side with the adhesive.

Overall, prelamination, lamination, adhering and gluing may all relate to applying an adhesive to at least one leather piece ending up with the adherence of two leather pieces.

The adhesive may most preferably be a thermoplastic co-polyamide web.

The thermoplastic co-polyamide web may e.g. have a DSC melting range between 98 to 145 and DSC onset at between 96 and 115 Celsius degrees according to ISO 11357.

A possible DSC melting range for an applied co-polyamide hot-melt glue could e.g. be 98 to 110 degrees Celsius. This would ensure a robustness to steam treatment during manufacture but also ensure that the leather attachment layers are securely fastened to the footwear when the footwear is subjected to stress, temperature and humidity under ambient conditions

A further possible DSC melting range for an applied hot-melt glue could e.g. be 132 to 148 degrees Celsius. This would ensure a robustness to steam treatment during manufacture but also ensure that the leather attachment layers are securely fastened to the footwear when the footwear is subjected to stress, temperature and humidity under ambient conditions. The melting point of these adhesive may thus be different and the applied heat (temperature) and duration of heating (time) must be chosen to melt the chosen adhesive without damaging or drying the leather layer(s) too much. Other parameters to be considered when heating includes e.g. thickness of the leather and the pressure during the process.

Advantages of using a non-woven thermoplastic co-polyamide web are that it maintains a high softness, flexibility and breathability of the material. Further, the application of the thermoplastic co-polyamide web is industrial applicable, easy to unroll and process with no air entrapment during lamination.

The adhesive foil may be cut into relevant pieces depending on application by suitable cutting tools prior to lamination or adherence to leather. The adhesive foil may also be applied to leather prior to cutting the adhesive foil into suitable pieces.

The heating of the adhesive thermoplastic co-polyamide web during prelamination may preferably be made by heating the web through a heat resistant paper from at least one heating element. The temperature from the heating element may be at least 100 Celsius degrees, more preferably at least 140 Celsius and most preferably at least 160 Celsius degrees. Preferably, the temperature during manufacture should not exceed 200 degrees Celsius.

The heating of the thermoplastic co-polyamide web during lamination of two leather pieces may preferably by made by heating the web through a leather piece directly linked to the web and another leather piece. The temperature from the heating element may be at least 100 Celsius degrees, more preferably at least 140 Celsius or at least 170 Celsius degrees.

The temperature applied to the leather may be different from temperature at the site of the thermoplastic co-polyamide web and several parameters can influence the differences between these temperatures. Such parameters could be the type of leather or pre-treatment of the leather, thickness of the leather, pressure during lamination and the time where the temperature and pressure are applied to the leather.

The temperature of both the leather side and the thermoplastic co-polyamide web are preferably controlled by e.g. a strip that indicate temperature to make sure that the correct temperature reaches the leather and thermoplastic co-polyamide web to ensure an optimal and strong binding.

The heating may be applied from only one side through one leather piece but may also be applied through both sides of the two leather pieces.

During pre-lamination, a heat resistant element, such as Teflon, e.g. a Teflon sheet 507 as illustrated in FIG. 5A-C, may be used between the heating part and the adhesive. The heat resistant element may be an individual component but may also be an integrated part of an apparatus.

The duration or time of heating may greatly affect the adherence og the thermoplastic co-polyamide web to the leather and the time may be different during the steps of prelamination and lamination. During prelamination the time may preferably be less than the time during lamination. The time of heating may preferably be at least 3 sec. during prelamination and preferably at least 30 sec. during lamination. The time of heating may be changed according to different parameters such as the type of leather or pre-treatment of the leather, thickness of the leather and pressure applied during the process.

The temperature applied during heating during pressure may depend on the type of hot-melt glue applied. If hot-melt glue with lower melting temperature than e.g. 130 degrees Celsius, the heating temperature may be lowered correspondingly,

The pressure applied to the leather and adhesive during the process may increase the thermal conductivity through the leather and thereby improve the heat transfer. Improving the heat transfer thorough the leather may influence how high temperature that needs to be applied to the leather in order to reach the melting temperature of the thermoplastic co-polyamide web.

The pressure applied during heating may vary depending on application, but the pressure should at least be 2 bar or above, such as at least 3 bar or above, such as at least 4 bar and above.

The step of cooling the hot-melted glue actively or passively should preferably be done under elevated pressure, enough to both fixate the bonded/gradually bonding leather layers and also ensure that the glue is kept within the non-woven fiber structures of the leather layers to the widest degree possible. Elevated temperature may be e.g. 1 bar, but it also makes sense to apply a pressure comparable to the pressure applied through heating.

It should be noted that the pressure applied during cooling may advantageously be applied in another machine than the machine applied during pressure and heating.

Leather pieces illustrated in the above description e.g. as exemplified in FIG. 5 as 505 may be any type of leather. Preferably the leather type is carefully selected based on its properties and chemicals used e.g. in pre-treatment of the leather e.g. during the tanning process.

Leather types that may be useful within the scope of the invention are types such as

Examples of leather types that may be used within the scope of invention may be types such as full grain or top grain leather, embossed grain leather, suede and nubuck.

Leather pieces may be cut out to relevant pieces depending on application by suitable cutting tools prior to lamination or adherence to adhesive. The leather may also be laminated or applied an adhesive prior to cutting the leather into suitable pieces.

The invention has been exemplified above with reference to specific examples of the parts of the shoe and methods of adhering parts of the shoe. However, it should be understood that the invention is not limited to the particular examples described above but may be designed and altered in a multitude of varies within the scope of the invention as specified in the claims.

In principle, the method may be carried out with any type of leather. However, typically the leather will have already been tanned and post tanned. Tanning and post tanning of leather is well known in the art and need not be described in detail here.

Any type of tanned leather may be used, including metal tanned (e.g. using chromium, aluminum, zirconium, titanium, iron or combinations thereof), vegetable tanned (e.g. using tannins from bark or other sources), or natural tanning. Typically, the leather is tanned with chrome or vegetable tanned, with chrome tanned leather being most often used.

In principle, there is no upper limit to the thickness of the leather used in the method. However, the reinforcing fabric provides strength to the laminate formed by the method, so the leather need not be overly thick. Moreover, if the leather is too thin, the adhesive can penetrate the entire thickness of the leather, fixing it and thus preventing the surface texture from developing during milling. Consequently, the leather is typically from 0.1 to 4 mm thick, more typically from 0.2 to 3.2 mm thick, or even 0.3 to 2 mm thick.

An advantage of the laminate is very thin leathers can be used which retain the unique surface texture obtainable by the method of the disclosure, are lightweight and flexible yet strong due to the reinforcing fabric. The laminates formed from thinner leathers are therefore particularly desirable.

Thinner leathers that are typically used include from 0.3 to 1.6 mm, or 0.3 to 1.2 mm, or even 0.3 to 0.9 mm, with 0.4 to 0.8 mm being the most preferred.

The method disclosed herein is most advantageous with thinner leathers, as the unique surface texture may be formed to provide very soft and supple leather. However, the leather is still very high strength due to the reinforcing layer, meaning that it can be used in a wide range of products.

Leather is a natural product that inevitably varies in thickness to some degree. Typically, the tolerated substance for a leather type is 0.2 mm, meaning that the sample thickness may vary by 0.2 mm over its area, such as 0.4-0.6 mm or 1.2-1.4 mm.

The thickness of leather can be calculated using Satra TM 1: 2004.

The thickness of a leather layer may e.g. be measured by a SATRA STD 483 “Thickness gauge for leather”

In principle, the leather can derive from any source, including cow hide, horse hide, goat skin, sheep skin, kangaroo hide and the like.

Leathers deriving from reptiles or fish have different surface properties on the skin side, and therefore develop a different surface texture during the method of the disclosure. Nevertheless, these types of leathers tend to have lower strengths (particularly fish leathers), and so can greatly benefit from being laminated to the reinforcing layer in accordance with the disclosure, to provide high strength laminates having unique surface textures.

Even so, preferably the leather is a mammal or marsupial leather (i.e. derives from a hide from a mammal such as a cow or horse, or a marsupial such as a kangaroo). Mammal leathers are most often used.

The method of the disclosure provides a characteristic and aesthetically pleasing surface texture to the second side of the leather. Typically, therefore the first side of the piece of leather is the flesh side, and the second side of the piece of leather is the skin side.

Desirably, the leather base layer and the leather attachment layers are top grain leather.

Tanning is used as the conventional ways of treating leather and may be applied to the invention. Depending on the compounds, the color and texture of the fabric may change. The technical definition of tanning is well known in the art, but briefly, according to Anthony D. Covington “Tanning Chemistry” chapter 10, the only strict definition of tanning is the conversion of a putrescible organic material into a stable material capable of resisting biochemical attack. Tanning involves a number of steps and reactions depending on the initial material and the final product. In the case of collagen, it is the sidechains that largely define its reactivity and its ability to be modified by the stabilizing reactions of tanning when leather is made. In addition, the chemistry of the backbone, defined by the peptide links, offers different reaction sites that can be exploited in some tanning processes. During the tanning process, modification of collagen by the chemistry of the tanning agent(s) affects the different features of the properties of the material; The hydrophilic—hydrophobic balance of the leather may be markedly affected by the chemistry of the tanning agent by changing the relationship between the leather and the solvent, which in turn could affect the equilibrium of any reagent between the solvent and the substrate. Also, the site of reaction between the reagent and the collagen may affect the isoelectric point of the collagen and consequently there could be a different relationship between pH and charge on the leather. The lower the isoelectric point, the more anionic or less cationic the charge on the pelt may be at any pH value: the higher the isoelectric point, the more cationic or less anionic the charge on the pelt will be at any pH value. Further, the relative reactions at the sidechains and the backbone of the protein could possible determine the type of reaction and hence the degree of stability of the tannage: the fastness of the reagent may be influenced by the interaction between reagents and the substrate.

Hydrothermal stability as used herein could possibly be measured through the shrinkage temperature (Ts) of a hide. This is the temperature at which the energy input (heat) exceeds the energy bound in existing hydrogen bonding of the collagen structure resulting in the decomposition of the helical structure. The shrinkage temperature for untanned hides is generally around 65 degrees Celsius. The Ts may be increased through the process of tanning.

Chromium(III) sulfate ([Cr(H2O)6]2(SO4)3) has long been regarded as the most efficient and effective tanning agent. Chromium(III) compounds of the sort used in tanning are significantly less toxic than hexavalent chromium. Chromium(III) sulfate dissolves to give the hexaaquachromium(III) cation, [Cr(H2O)6]3+, which at higher pH undergoes processes called olation to give polychromium(III) compounds that are active in tanning being the cross-linking of the collagen subunits. The chemistry of [Cr(H2O)6]3+ is more complex in the tanning bath rather than in water due to the presence of a variety of ligands. Some ligands include the sulfate anion, the collagen's carboxyl groups, amine groups from the side chains of the amino acids, and masking agents. Masking agents are carboxylic acids, such as acetic acid, used to suppress formation of polychromium(III) chains. Masking agents allow the tanner to further increase the pH to increase collagen's reactivity without inhibiting the penetration of the chromium(III) complexes.

Collagen is characterized by a high content of glycine, proline, and hydroxyproline, usually in the repeat -gly-pro-hypro-gly-. These residues give rise to collagen's helical structure. Collagen's high content of hydroxyproline allows for significant cross-linking by hydrogen bonding within the helical structure. Ionized carboxyl groups (RCO2-) are formed by hydrolysis of the collagen by the action of hydroxide. This conversion occurs during the liming process, before introduction of the tanning agent (chromium salts). The ionized carboxyl groups coordinate as ligands to the chromium(III) centers of the oxo-hydroxide clusters.

Tanning increases the spacing between protein chains in collagen from 10 to 17 Å. The difference is consistent with cross-linking by polychromium species, of the sort arising from olation and oxolation.

One way of performing a tanning is explained in the following. Prior to the introduction of the basic chromium species in tanning, several steps are required to produce a tannable hide. The pH must be very acidic when the chromium is introduced to ensure that the chromium complexes are small enough to fit in between the fibers and residues of the collagen. Once the desired level of penetration of chrome into the substance is achieved, the pH of the material is raised again to facilitate the process. This step is known as basification. In the raw state, chrome-tanned skins are greyish-blue, so are referred to as wet blue. Chrome tanning is faster than vegetable tanning (less than a day for this part of the process) and produces a stretchable leather which is excellent for use in handbags and garments.

Subsequent to application of the chromium agent, the bath is treated with sodium bicarbonate to increase the pH to 4.0-4.3, which induces cross-linking between the chromium and the collagen. The pH increase is normally accompanied by a gradual temperature increase up to 40° C. Chromium's ability to form such stable bridged bonds explains why it is considered one of the most efficient tanning compounds. This efficiency is characterized by its increased hydrothermal stability of the skin, and its resistance to shrinkage in heated water.

The leather of a leather layer may typically comprise tanning agents in the amount of 3 to 12% by weight of the leather layer when the tanning agents includes chrome tanning agents.

The chrome tanning agents includes chromium, chromium salts and/or derivatives thereof.

The leather may as a further restriction in relation to the total content of tanning agent in the leather comprise chrome tanning agent(s) in the amount of 1 to 7% by weight of the leather, such as 2 to 6% by weight of the leather such as 2 to 5% by weight of the leather.

The specific content of chrome tanning in the amount of 1 to 7% by weight of the leather, such as 2 to 5% by weight of the leather is in particular attractive in relation to the inventive leather bonding as this content of chrome in the leather of the leather layers bonded makes is possible to use heat-activated adhesive to attach the leather to the reinforcing fabric. It is moreover, and even more advantageous in applications where the leather as to be steamed e.g. for purposes of shaping etc.

The chrome tanning agents includes chromium, chromium salts and/or derivatives thereof.

Fatliquoring refers to the process where fats/oils and waxes are fixed to the leather fibers. The primary function of fatliquoring is to prevent the fiber structure resticking during drying by providing an oil surface to the fiber structure. Any fatliquoring agents may be used, including anionic fatliquors such as sulfonated fatliquors and sulfited oils, soap fatliquors and cationic fatliquors. Nonionic fatliquors may also be used, including alkyl ethylene oxide condensates and protein emulsifiers. Multicharged fatliquors that are formulations of non-ionic, anionic and cationic fatliquors, may also be used for the fatliquoring process.

Raw material for the fatliquoring agents may be sea animal oils such as fish oil; land animal oils and fats such as claw oil, beef tallow, pig fat and bone fat; Vegetable oils and fats such as palm oil, sunflower oil, rapeseed oil, soybean oil, coconut fat, palm kernel fat and turkey red oil; waxes such as carnauba wax, montan wax and wool grease; synthetic fats such as paraffin oil, mineral oil, fatty alcohol and fatty acid ester.

It should generally be noted that further parts of a footwear may be made according to other methods or with further different means than the claimed leather assembly as long as least one part of the footwear is made with these inventive provisions or at least where leather layers have been bonded according to the inventive method.

The focus of the present application has generally been to improve parts of an upper of a footwear and no detailed information has been given regarding the fitting of an upper according to the provision of the invention to a sole, but it is within the ability of the skilled person to e.g. attach the upper to the sole by means of conventional cementing or injection molding.

In an embodiment of the invention, the only bonding of the two leather pieces, i.e. a leather base layer and a leather attachment layer is obtained through gluing.

In an embodiment of the invention, the only bonding of the two leather pieces, i.e. a leather base layer and a leather attachment layer is obtained through gluing.

In an embodiment of the invention, the footwear is stitch free.

The method described within the scope of the invention, wherein at least two leather pieces are bonded without stitches is advantageous. However, besides this method, other methods of adhering other leather pieces together in the resulting footwear may be applied either as replacing or by supplementing the gluing by other methods. Other methods that may be applied for other than the inventive bonding could e.g. be processes such as sewing including stitching or other relevant methods where stiches are applied in any kind.

Generally, when referring to cow as a source of hide for the leather, the reference refers to both calf or cow hides.

FIG. 9 illustrate an automatic footwear processing arrangement AFPA and different units to be applied within such a system.

The automatic footwear processing arrangement AFPA includes a number of units which may be applied in a footwear manufacturing line within the scope of the invention. Units may in the present context include separate units which may be gathered in other units or sub arrangements or a unit may be constructed as an arrangement including several co-operating units.

The automatic footwear processing arrangement AFPA include individual or co-working units as mentioned and described below.

The overall automatic footwear processing arrangement is designed to produce footwear or parts of footwear and the co-working units are configured to process leather footwear parts to be included in the manufacturing line. Footwear parts may typically refer to parts of a footwear which may be understood as a leather base layer LBL and a leather attachment layer LAL in relation to the inventive bonding within the scope of the invention.

The automatic footwear processing arrangement AFPA includes an input I and an output O.

Different further units may include a leather cutting arrangement LCA. The leather cutting arrangement may be configured for cutting out leather footwear parts, such as leather vamps, leather quarters, leather heels, etc. from larger leather layers. The footwear parts may also elsewhere in this application be more broadly referred to as a leather base layer LBL or a leather attachment layer LAL.

The arrangement may be configured for switching between different types, styles or designs of footwear parts and the output of the arrangement may not necessarily only be exactly one type of footwear part due to the fact that the subsequent adhesion between two footwear parts within the scope of the invention may be performed on different footwear parts and switch between footwear parts during the stacking process to follow. This is a completely different approach from stitching based lines, where such switch is basically impossible or pretty complex with today's stitching technologies.

A further unit may include a pre-adhesion processing arrangement PAPA. This unit is applied for automatically preparing the leather footwear parts for the subsequent bonding to other parts. This process may typically include removal of dust by suction, brushes or other applicable processes to ensure that the leather parts to be adhered are extremely clean as it has been experienced that contamination, e.g. from dust, fat, etc., may result in inferior final bonding of the footwear parts to be adhered. The automatic performing of this particular step is a great improvement in any footwear manufacturing line where leather parts of the footwear is to be bonded by adhering.

The pre-adhesion processing arrangement PAPA may include a number of preparation steps, including the above-mentioned, and the steps may be run according to pre-determined routines, i.e. a fixed number of pre-determined steps and the steps may each perform the pre-programmed task, e.g. at given time durations. This predetermined configuration may of course be changed and fit to the specific leather footwear parts to be processed. An alternative to such a pre-determined configuration is dynamically to adapt the process to the leather footwear parts in question e.g. by measuring data indicative of the state of the leather parts and thereby insert different steps, modify how steps are executed e.g. with respect to time.

A further unit must include an automatic stacking arrangement ASA. In this arrangement, two or more input footwear parts, i.e. at least a leather base layer LBL and a leather attachment layer LAL are automatically stacked to be at least partly overlapping. The stacking arrangement may be used simply to stack as the last preparation for activation of adhesive if the footwear parts have been pre-adhered with adhesive which may be activated after stacking. Alternatively, the unit may include a pre-adhering arrangement applying adhesive to the footwear parts previous to stacking or during stacking. The adhesive may be any of the types elsewhere referred to in this application, e.g. thermo adhesive, adhesive to be activated by radiation (e.g. UV), adhesive to be activated by chemistry etc. The pattern in which the adhesive is applied to the footwear parts may by performed automatically to ensure that the adhesive is only applied to where subsequent bonding is required. Alternative ways of applying adhesive may be to automatically position adhesive in the form of solid webs between the footwear parts.

The stacked footwear parts are then supplied to an automatic adhesive activation arrangement AAA. The arrangement is designed to activate the adhesive between the stacked parts. The activation may e.g. be by heating, radiation, ultrasonic, chemistry or any suitable way by means of which the desired activation and subsequent bonding may be obtained.

The stacked footwear parts, now with activated adhesive, may subsequently or simultaneously be subjected to pressure by an automatic pressure activation arrangement APA. This unit may be included in the above adhesive activation arrangement so as to subject the footwear leather parts to pressure and activation at the same time.

Subsequently the stacked and activated footwear parts are subjected to curing in an automatic curing arrangement ACA. This arrangement may be included in the above two arrangements or the stacked and activated footwear parts may be handed from the above units/arrangements to the automatic curing arrangement ACA as long as the footwear parts are still forced together under pressure until a sufficient bonding is obtained. The curing process, including control of temperature (actively), use of ambient temperature both at a predetermined time duration or e.g. dynamically determined by measuring of relevant process parameters or leather part parameters during the process. An efficient automatic control of curing time ensures the desired reliable bonding.

The curing may e.g. also, more specifically in relation to thermo activated adhesive, be performed by means of an optional automatic cooling arrangement ACOA.

Subsequent the bonded two or more footwear parts may be reintroduced into the system for automatic bonding to further leather footwear parts or it may be transferred automatically or manually into a finalization step where the footwear is finalized, e.g. with other footwear parts. The finalization may include manual process step in particular in relation to the process of converting the bonded 2D footwear parts into a 3D upper. Such process may include some manual but very limited stitching or even adhesion and then the footwear may be gathered with a sole, e.g. by cementing of the upper to a premade sole or by direct-injection of the sole to the upper and thereby outputting a final 3D footwear.

Subsequent process steps or supplementary process steps may be applied within the scope of the invention.

FIG. 10 a-c illustrate different embodiments of footwear processing equipment within the scope of the invention, where the inventive method is applied automatically in at least significant parts of the manufacturing line.

As illustrated in FIGS. 10 a-c , the processing arrangement may include that processed footwear parts subsequently are subjected to further steps, including automated footwear manufacturing AFM.

It should be noted that footwear comprising leather up until now during ages has been restricted or focused on applying stitching during the main process steps of the manufacturing of footwear. This is due to the fact that leather is extremely difficult to handle and adhesion may mainly have been applied for the purpose of attaching gadgets or used in other minor process steps where strength is not really an issue.

This is particular true in relation to stitching along the circumference or parts of circumferences of footwear parts, such as vamp, quarters, heel and/or tongue.

The illustrated configurations 10 a-c are all within the scope of the invention with one or more of the illustrated units/arrangements as described in FIG. 10 .

FIG. 11 a-d illustrate various arrangements and devices for footwear processing and production according to embodiments of the invention.

FIG. 11 a illustrates a leather cutting arrangement LCA which is configured to receive at least one or more leather parts L, which it cuts into several leather parts for footwear production. These leather parts may for example include one or more leather base layers LBL and one or more leather attachment layers LAL, but it is not restricted to these types of leather footwear parts. A leather cutting arrangement may for example be an automated leather cutting arrangement which is at least partially automated. An automated leather cutting arrangement LCA may for example receive input from a sensor, a camera, or a visual detection system for guiding, planning, and/or steering the placement and cutting of leather. Embodiments of the invention may comprise more than one leather cutting arrangement LCA, for example two or more leather cutting arrangements LCA which each cut out a different type of leather footwear part.

FIG. 11 b illustrates a pick-and-place device PAPD which is configured to receive at least one or more footwear parts, for example leather attachment layers LAL and leather base layers LBL, and place these parts and a particular pattern, for example a pre-programmed pattern. The purpose of this operation may for example be to prepare these footwear parts for further operations, such as application of adhesive. A pick-and-place device may for example be at least partially automated. An automated pick-and-place device PAPD may for example receive input from a sensor, a camera, or a visual detection system for guiding, planning, and/or steering the picking and placement of footwear parts.

FIG. 11 c . illustrates an adhesive application arrangement AAPA which is configured to apply adhesive A onto one or more leather parts, for example leather base layers LBL and/or leather attachment layers LAL. Adhesive A is for example be applied in the form of a web, a foil, or a liquid in a particular pattern, but note that application of adhesive is not restricted to any of these examples. In the exemplary adhesive application arrangement shown in FIG. 11 c , the adhesive A is applied to the leather base layers LBL in the regions in which leather attachment layers LAL are to be attached to the leather base layers. An adhesive application arrangement AAPA may be at least partially automated. An automated adhesive application arrangement AAPA may for example receive input from a sensor, a camera, or a visual detection system for guiding, planning, and/or steering the application of the adhesive A. In some embodiments, an automated adhesive application arrangement AAPA relies on the placement of footwear parts as performed at a prior step of a production line, e.g. placement performed by a pick-and-place device PAPD.

FIG. 11 d illustrates an automated stacking arrangement ASA which is configured to stack leather base layers LBL and leather attachment layers LAL, for example such that adhesive is situated between these layers LBL, LAL. This stacking can for example prepare the footwear parts and the adhesive the activation of the adhesive. An automated stacking arrangement ASA may for example receive input from a sensor, a camera, or a visual detection system for guiding, planning, and/or steering the stacking of footwear parts. In some embodiments, an automated stacking arrangement ASA relies on the placement of footwear parts as performed at a prior step of a production line, e.g. placement performed by a pick-and-place device PAPD.

FIG. 12 a-d illustrate additional various arrangements and devices for footwear processing and production according to embodiments of the invention.

FIG. 12 a illustrates an automatic pressure activation arrangement APA, which is arranged to apply pressure to at least one footwear part, for example at least one leather base layer LBL, at least one leather attachment layer LAL, and/or any adhesive A between at least one leather base layer LBL and at least one leather attachment layer LAL. The pressure of the automated pressure activation arrangement may for example be applied by one or more automatic pressure activation arrangement parts APAP1, APAP2. In the exemplary embodiment shown in FIG. 12 a , two automatic pressure activation arrangement parts APAP1, APAP2 apply pressure to an assembly of leather base layers LBL, adhesive A, and leather attachment layers LAL which are layered between the two parts APAP1, APAP2. Other parts relevant for the manufacturing process may also be located between the two automatic pressure activation arrangement parts APAP1, APAP2 during the application of pressure, for example a fixture base layer, a Teflon sheet or similar, a production tray, or other footwear parts. In some embodiments of the invention, the bottom automatic pressure activation arrangement part APAP2 is a conveyer belt of a footwear production line, and the pressure is applied by forcing the top automatic pressure activation arrangement part APAP1 downwards onto the assembly of footwear parts and adhesive located on the conveyer belt.

FIG. 12 b illustrates an automatic adhesive activation arrangement AAA, which is arranged to activate adhesive A, at least partly automatic, for example fully automatic. In the exemplary embodiment illustrated in FIG. 12 b , two automatic adhesive activation arrangement parts AAAP1, AAAP2 are in thermal contact with an assembly of leather base layers LBL, adhesive A, and leather attachment layers LAL which are layered between the two parts AAAP1, AAAP2. Other parts relevant for the manufacturing process may also be located between the two automatic adhesive activation arrangement parts AAAP1, AAAP2 during the activation of adhesive, for example a fixture base layer, a Teflon sheet or similar, a production tray, or other footwear parts.

This embodiment is arranged to active the adhesive A by heating, e.g. be heating either one or both automatic adhesive activation arrangement parts AAAP1, AAAP2, such that a thermoplastic adhesive A becomes pliable or moldable. In some embodiments of the invention, the bottom automatic adhesive activation arrangement part AAAP2 is a conveyer belt of a footwear production line. In this exemplary embodiment, the adhesive is activated using contact heating, but in other embodiments, the adhesive can also, for example, be activated using radiation, IR radiation, UV radiation, ultrasonics, chemistry, or any other suitable way by means of which the desired activation and subsequent bonding may be obtained. In any embodiment, the geometry of the automatic adhesive activation arrangement AAA is arranged to allow the adhesive to be activated, e.g. if the adhesive is activated by using radiation, the shape of the automatic adhesive activation arrangement parts AAAP1, AAAP2 allow the radiation to be applied to activate the adhesive.

FIG. 12 c illustrates an automatic curing arrangement ACA, which is arranged to hold an assembly of one or more leather footwear parts LBL, LAL and adhesive A while the adhesive A cures. The curing of the adhesive can for example deform the adhesive slightly, and therefore, holding an assembly in place may ensure a more precise and accurate production of footwear. In the exemplary embodiment illustrated in FIG. 12 c , two automatic curing arrangement parts ACAP1, ACAP2 are holding an assembly of leather base layers LBL, adhesive A, and leather attachment layers LAL which are layered between the two parts ACAP1, ACAP2. The two parts ACAP1, ACAP2 can for example hold the assembly by means of pressure, e.g. in a manner similar to an automatic pressure activation arrangement APA. Other parts relevant for the manufacturing process may also be located between the two automatic curing arrangement parts ACAP1, ACAP2 during the curing of adhesive, for example a fixture base layer, a Teflon sheet or similar, a production tray, or other footwear parts.

FIG. 12 d illustrates an automatic cooling arrangement ACOA, which is arranged to cool an assembly of one or more leather footwear parts LBL, LAL and adhesive A, and cool the assembly, e.g. after heating has been applied to activate the adhesive A.

In the exemplary embodiment illustrated in FIG. 12 d , two automatic cooling arrangement parts ACOAP1, ACOAP2 are in thermal contact with an assembly of leather base layers LBL, adhesive A, and leather attachment layers LAL which are layered between the two parts ACOAP1, ACOAP2. Other parts relevant for the manufacturing process may also be located between the two automatic cooling arrangement parts ACOAP1, ACOAP2 during the cooling, for example a fixture base layer, a Teflon sheet or similar, a production tray, or other footwear parts. In some embodiments, the cooling may be active in the sense that energy is used to perform the cooling, e.g. by using a thermoelectric device or by circulation of a coolant, e.g. as part of a refrigeration cycle or by air cooling using a fan. In some embodiments, the cooling may be passive, in the sense that no energy is used to perform the cooling, e.g. heat is dissipated away from the assembly to a heat sink.

In some embodiments of the invention, any of an automatic pressure activation arrangement APA, an automatic adhesive activation arrangement AAA, an automatic curing arrangement ACA, and an automatic cooling arrangement ACOA may be combined into a single device/arrangement. For example, a combined arrangement may apply pressure to an assembly of leather base layers LBL, adhesive A, and leather attachment layers LAL which are layered between the two parts of the arrangement. These two parts are in thermal contact with the assembly and are heated to activate the adhesive. Next, the two parts are cooled, e.g. actively cooled, to cure the adhesive.

FIG. 13 illustrates a further various arrangements and devices for footwear processing and production according to embodiments of the invention. Particularly, a conveyer belt CB, a three-way transfer 3WT, a visual detection system VDS, and a quality inspection system QIS is shown.

The conveyer belt CB is arranged to transport footwear parts or assemblies such as an assembly of at least one leather base part, at least one leather attachment part, and/or adhesive along a footwear production line. The parts or the assembly may for example be transported directly on the conveyer belt CB, may be attached to a fixture which is transported on the conveyer belt CB, or may located on a production tray which is transported on a conveyer belt CB. In some embodiments of the invention, footwear parts are moved along a production line using other types of conveyer systems. In some embodiments, the footwear is at least partly produced at a production station without using any of conveyer.

In the illustrated embodiment, the conveyer belt CB is associated with a visual detection system VDS. The visual detection system is arranged to survey footwear parts or assemblies on the production line. It may for example be based on cameras and/or sensors, and it may for example be arranged to detect anomalies, flaw, or inaccuracies in the footwear parts or assemblies. A visual detection system may thus for example be used to detect inaccurate cutting of a leather footwear piece, inaccurate application of adhesive, inaccurate placement or stacking of footwear parts etc. Based on the visual detection system, the production line may be manually and/or automatically arranged to handle such inaccuracies, for example using a three-way transfer 3WT.

In the illustrated embodiment, the conveyer belt CB and the visual detection system VDS is associated with a three-way transfer 3WT, which is arranged to act upon output of the visual detection system VDS. The three-way transfer 3WT may for example be a part of a production line and may be arranged to receive one or more items from the left side (of the illustration), and may either transfer these to the right side (of the illustration) or upwards (relative to the illustration), for example upwards to a quality inspection system QIS. The three-way transfer system is further arranged to receive items from the upwards direction and transfer these to the right side. As an example, the three-way transfer may be arranged to receive footwear parts and/or a footwear assembly and then either transfer any of these forward on the production line, and/or transfer any of these off the production line to a quality inspection system QIS based on input from the visual detection system. Further, the embodiment is arranged to receive footwear parts and/or a footwear assembly from the quality inspection system QIS and pass any of these forward on the production line. In other embodiments, the three-way transfer 3WT is associated with other modules than a quality inspection system QIS, for example any of a leather cutting arrangement LCA, a pick-and-place device PAPD, an adhesive application device AAPA, an automatic staking arrangement ASA, an automatic adhesive activation arrangement AAA, an automatic pressure activation arrangement APA, an automatic curing arrangement ACA, an automatic cooling arrangement ACOA, an automatic cutting arrangement ACUA, an automatic stitching arrangement ASTA, a fixture preparation module FPM, a sole attachment process SAP, a stacking device STA, etc.

A quality inspection system QIS may for example be arranged to detect inaccurate cutting of a leather footwear piece, inaccurate application of adhesive, inaccurate placement or stacking of footwear parts etc., for example using sensors, a camera, and/or manual inspection. For example, a visual detection system VDS may move items off the production line which are under suspicion of being incorrectly or inaccurately produced, and the quality inspection system may confirm or reject this suspicion, for example based on further measurements of the visual detection system VDS, based on measurements from an auxiliary visual detection system, and/or based on manual inspection. Any item, e.g. footwear part or assembly, which passes inspection is reintroduced onto the production line via the three-way transfer, for example via an automatic transfer after an automatic inspection, or at least partly manually after an at least partly manual inspection. A visual detection system VDS and/or a quality inspection system QIS may for example be based on comparison of one or more footwear parts with one or more reference images of those one or more footwear parts, to check whether those one or more footwear parts lies within a threshold tolerance of the one or more reference images.

FIG. 14 a-d illustrate a robot and different kinds of robot tools for footwear processing according to embodiments of the invention. Namely, FIG. 14 a show a robot arm RARM attached to a robot tool RTOO which is a robot gripper RGRI, while FIG. 14 b-c show other types of robot tools RTOO which are may also be used in collaboration with a robot arm RARM for footwear processing.

In embodiments of the invention, a robot may for example be an integrated as part of a three-way transfer 3WT, a quality inspection system QIS, a leather cutting arrangement LCA, a pick-and-place device PAPD, an adhesive application device AAPA, an automatic staking arrangement ASA, an automatic adhesive activation arrangement AAA, an automatic pressure activation arrangement APA, an automatic curing arrangement ACA, an automatic cooling arrangement ACOA, an automatic cutting arrangement ACUA, an automatic stitching arrangement ASTA, a fixture preparation module FPM, a sole attachment process SAP, a stacking device STA, etc.

In embodiments of the invention, a robot may for example be a robot arm, an articulated robot, a SCARA robot, a delta robot and a cartesian coordinate robot, but note that robots are not restricted to a particular type, and a skilled person may select any type of robot for a given part of a production line that skilled person finds suitable. A robot may for example be programmed to repetitively carry out specific actions over and over with a high degree of accuracy, for example relying on exact placement of footwear parts. A robot may also rely on e.g. a visual detection system VDS to locate footwear parts and perform a required operation. The robot illustrated in FIG. 14 a is a six-axis robot arm RARM, which allows the robot tool RTOO to be moved at any angle to any location within the limitations of the robot arm RARM.

The robot arm RARM in FIG. 14 a is attached to a robot gripper RGRI, which allows it to pick up and place items such as footwear parts, such as leather base layers LBL and leather attachment layers LAL. Such a robot tool may for example be a part of a pick-and-place device PAPD or an automatic stacking arrangement ASA. FIG. 14 b show a part of another robot tool RTOO which is a robot stitching tool RSTI. A robot stitching tool RSTI may for example be used to stitch footwear parts together, for example 2D footwear parts or 3D footwear parts, for example as a supplement to adhesive. FIG. 14 c show a part of another robot tool RTOO which is a robot adhesive appliance tool RAAP, which may be used to apply adhesive. Particularly, the illustrated robot tool is capable of applying a liquid adhesive, but other robot tools may be capable of delivering other types of adhesive, for example in the form of a foil or a web. FIG. 14 d show a part of another robot tool RTOO which is a robot vacuum gripper RVAC, which may be used to pick up and place items such as footwear parts. In other embodiments, a robot tool may for example be used to force the leather base layer LBL and the leather attachment layer LAL against each other under a pressure, to activate the adhesive, to cool or cure the adhesive etc.

FIG. 15 a-c illustrate attachment of footwear parts LBL, LAL to a fixture FIX according to embodiments of the invention. A fixture FIX may for example be used to facilitate transportation of footwear parts, for example along a conveyer. It may further fix footwear parts in relation to each other, and/or fix them relative to an automated footwear processing arrangement, for example via one or more reference points of the fixture FIX, which an automated footwear processing arrangement may be operated relatively to. Additionally, a fixture FIX may comprise an identifier, for example to identify any footwear parts on the fixture. Further, a fixture FIX may provide a fixture base layer FBL, which may serve as lining in the finalized footwear.

FIG. 15 a illustrate the fixture FIX comprising a frame FRA which holds a fixture base layer FBL. The fixture FIX may be configured in a multitude of variations, but in this illustration, it is seen in a perspective view partly from above and partly from the side, being in an essentially rectangular geometry. The fixture base layer FBL is arranged to be attached to footwear parts, for example leather footwear parts, for example a leather base layer. The attachment may be carried out using preliminary adhesive, adhesive, gluing, stitching, clamping etc. In some embodiments, the fixture base layer FBL and any attached footwear parts are cut out from the frame FRA, e.g. by a manual or an automated process, for example such that the part of the fixture base layer FBL which is attached to the footwear parts can be used as lining in the further production of the footwear.

FIG. 15 b illustrate a fixture FIX, which is essentially similar to the fixture FIX illustrated in FIG. 15 a , but with two attached leather base layers LBL. Such footwear parts LBL may for example be placed on the fixture base layer FBL using a pick-and-place device PAPD and/or an automated stacking arrangement ASA. The footwear parts may for example be placed on the fixture FIX relative to a reference point of the fixture FIX, e.g. a corner of the fixture FIX.

FIG. 15 c illustrate a fixture FIX, which is essentially similar to the fixture FIX illustrated in FIG. 15 b , but with three leather attachment layers LAL on top of the leather base layers LBL. Such footwear parts LAL may for example be placed on the leather base layers LBL on the fixture base layer FBL using a pick-and-place device PAPD and/or an automated stacking arrangement ASA, for example after application of adhesion by an automated adhesion application arrangement AAPA. The footwear parts LAL may for example be placed on the fixture FIX relative to a reference point of the fixture FIX, e.g. a corner of the fixture FIX.

Footwear parts LBL, LAL may be attached to a fixture FIX as exemplified in FIG. 15 c during any steps of an automated footwear processing arrangement AFPA. At some a later point in the production, the footwear parts may then for example be detached from the fixture FIX or the fixture base layer FBL may be cut from the frame FRA, for example such that the fixture base layer FBL can serve as lining for the footwear being produced.

FIG. 16 a-c illustrate footwear parts LBL, LAL in a production tray PT according to embodiments of the invention. A production tray PT may for example be used to facilitate transportation of footwear parts, for example along a conveyer. It may further be used to place footwear parts in relation to each other, and/or place them relative to an automated footwear processing arrangement, for example via one or more reference points of the production tray, which an automated footwear processing arrangement may be operated relatively to. Additionally, a production tray PT may comprise an identifier, for example to identify any footwear parts on the production tray PT.

FIG. 16 a illustrate the production tray PT seen in a perspective view partly from above and partly from the side, being in an essentially rectangular geometry with a ridge along its perimeter. However, the production tray PT may be configured in a multitude of variations. It is not restricted to any particular shape or material, but should merely allow facilitation of transportation of footwear parts such as at least one leather base layer LBL and/or at least one leather attachment layer LAL. However, a production tray PT is not limited to transport and particular footwear parts.

FIG. 16 b illustrate a production tray PT which is essentially similar to the production tray PT illustrated in FIG. 16 a , but in FIG. 16 b footwear parts has been placed in the production tray PT, namely leather base layers LBL and leather attachment layers LAL. The footwear parts may for example be placed in the production tray PT by a pick-and-place device PAPD. The footwear parts LBL, LAL have not necessary been attached in any way to the production tray PT. In some embodiments, the surface of the production tray PT ensures a friction force between footwear parts LBL, LAL and the tray PT, such that the footwear parts to not move substantially during conveyance or transport of the tray PT. The footwear parts LBL, LAL may for example be placed on the production tray PT relative to a reference point of the tray PT, e.g. a corner of the tray PT.

FIG. 16 c illustrate a production tray PT which is essentially similar to the production tray PT illustrate in FIG. 16 b , but in FIG. 16 c the leather base layers LBL have been stacked on top of the leather attachment layers LAL. This stacking may for example have been performed by an automatic stacking arrangement ASA after adhesive have been applied, for example by an automatic adhesive application arrangement AAPA.

FIG. 15 a-c and FIG. 16 a-c and the associated text has described various procedures for facilitating transportation of footwear parts during automatic production within the scope of the invention. In some embodiments, footwear parts may lay directly on a conveyer belt and be transported to different production steps along a production line. In some embodiments, at least one footwear part is connected to a jig, for example attached to a jig, and the jig facilitates transportation of that at least one footwear part. In some embodiments, footwear parts are moved by robots, e.g. robot arms. In some embodiments, footwear parts are moved manually, for example moved manually to different steps of a production line. In some embodiments, the footwear parts are assembled at a production station with no or minimal conveyance/transport.

FIG. 17 a-c illustrate various adhesive activation arrangements AAA according to embodiments of the invention.

FIG. 17 a illustrate an adhesive activation arrangement AAA based on resistive heating. Two adhesive activation arrangement parts AAAP1, AAAP2 are in thermal contact with an assembly of leather base layers LBL, adhesive A, and leather attachment layers LAL which are layered between the two parts AAAP1, AAAP2. Resistive elements are integrated in any of the first adhesive activation arrangement part AAAP1 and the second adhesive activation arrangement part AAAP2. A resistive element may heat up when an electric current is supplied to it through Joule heating/resistive heating/Ohmic heating, and dissipate the heat to its surroundings, e.g. footwear parts. In this manner, a thermoplastic adhesive may for example be activated. Any resistive elements may receive current from at least one driver DRI, which is controlled by a controller CTR. The controller CTR may for example be arranged to automatically activate the driver DRI as part of a fully or partly automated footwear production line. In some embodiments, the driver DRI is activated based on manual input, for example a switch.

FIG. 17 b illustrate an adhesive activation arrangement AAA based on infrared radiation. An infrared radiation emitter IRA is located in the vicinity of footwear parts LBL, LAL which are to be bonded with each other using adhesive A. When infrared radiation is emitted from the infrared radiation emitter IRE, the footwear parts and/or the adhesive may thus be heated, for example to activate a thermoplastic adhesive. The infrared radiation emitter IRE may receive a driving signal from a driver DRI, which is controlled by a controller CTR. The controller CTR may for example be arranged to automatically activate the driver DRI as part of a fully or partly automated footwear production line. In some embodiments, the driver DRI is activated based on manual input, for example a switch.

Other embodiments of the invention employ an adhesive activation arrangement AAA which is essentially similar to the adhesive activation arrangement AAA shown in FIG. 17 b , but with a different type of radiation, for example UV radiation, visible spectrum radiation, LED radiation, or laser radiation.

In some embodiments, an infrared radiation emitter is used to bond adhesive to one leather part, e.g. a leather base layer LBL or a leather attachment layer, in contrast to bonding to two leather parts simultaneously. When only bonding an adhesive to a single leather footwear part, it is possible to more efficiently heat up the adhesive, since another footwear part does not necessarily block the line of sight from the infrared radiation emitter IRE to the adhesive A. After bonding the adhesive A to a first leather part, another second layer part may then be stacked with the first leather part prior to a second adhesive activation step.

FIG. 17 c illustrate adhesive activation arrangement AAA based on ultrasonic acoustic vibrations. Two adhesive activation arrangement parts AAAP1, AAAP2 are in vibrational contact with an assembly of leather base layers LBL, adhesive A, and leather attachment layers LAL which are layered between the two parts AAAP1, AAAP2. Ultrasonic transducers UT are attached to the first adhesive activation arrangement part AAAP1 and the second adhesive activation arrangement part AAAP2. An ultrasonic transducer UT is able to generate ultrasonic energy based on a driving signal. In this embodiment, the driving signal is provided by at least one driver DRI. Preferably, the ultrasonic transducers UT and the driving signal/driver DIR are configured such that an ultrasonic signal is emitted from at least one of the ultrasonic transducers UT and such that energy of that ultrasonic signal reaches footwear parts and/or the adhesive.

In the illustrated embodiment, one ultrasonic transducer UT is attached to each of the two adhesive activation arrangement parts AAAP1, AAAP2. In some embodiments, no ultrasonic transducers are attached to one of the two parts AAAP1, AAAP2. In some embodiments, more than one, for example two, three, four, five, six, or more than six, ultrasonic transducer UT is attached to one or both of the two parts AAAP1, AAAP2.

In some embodiments, adhesive activation is based on acoustic vibrations in the range from 20 kHz to 100 kHz, for example ultrasonic frequencies from 20 kHz to 100 kHz, such as from 20 kHz to 70 kHz, e.g. 20 kHz, 30 kHz, 35 kHz, 40 kHz or 70 kHz. In some embodiments, adhesive activation is based on acoustic vibrations in the range from 10 kHz to 20 kHz, for example 15 kHz.

Any ultrasonic transducer UT may receive a driving signal from at least one driver DRI, which is controlled by a controller CTR. The controller CTR may for example be arranged to automatically activate the driver DRI as part of a fully or partly automated footwear production line. In some embodiments, the driver DRI is activated based on manual input, for example a switch.

FIG. 18 a-e illustrate exemplary steps of applying an adhesive activation arrangement AAA to footwear parts according to embodiments of the invention. The adhesive activation arrangement AAA comprises a first adhesive activation arrangement part AAAP1 and a second adhesive activation arrangement part AAAP2. Each part AAAP1, AAAP2 is attached to attached to at least one ultrasonic transducer UT. Each ultrasonic transducer may for example be driven by a driver DRI (not shown), which in turn is controlled by a controller CTRs (not shown).

FIG. 18 a illustrates a first exemplary step. The adhesive activation arrangement AAA is in an idle configuration, where it is ready to at least one footwear part and adhesive, for example a leather base layer LBL stacked with a leather attachment layer LAL with adhesive A stacked between the two leather layers. An angled open configuration of the first adhesive activation arrangement part AAAP1 allows footwear parts to be inserted into the adhesive activation arrangement AAA. However, note that adhesive activation arrangements AAA according to the invention are not restricted to being able to open by angling a first adhesive activation arrangement part AAAP1.

FIG. 18 b illustrates a second exemplary step. Here, a leather base layer LBL stacked with adhesive and a leather attachment layer LAL has been inserted into the adhesive activation arrangement AAA. Such an insertion may for example be performed automatically be a conveyer system or a robot, e.g. a robot arm.

FIG. 18 c illustrates a third exemplary step. After insertion of the footwear parts and the adhesive, the adhesive activation arrangement AAA is closed, for example by moving the first adhesive activation arrangement part AAAP1 down on top of the footwear parts, such that the assembly of leather base layers LBL, adhesive A, and leather attachment layers LAL are stacked between the two parts APAP1, APAP2. In this configuration, one or both of the adhesive activation arrangement parts AAAP1, AAAP2 may apply pressure to the footwear parts.

FIG. 18 d illustrates a fourth exemplary step. Here, the ultrasonic transducers UT emit ultrasonic radiation to activate, e.g. heat, the adhesive, as indicated by circular arcs in the adhesive activation arrangement parts AAAP1, AAAP2. Accordingly, these parts should be made in a material which allows the ultrasonic radiation/ultrasonic signal to propagate through to the footwear parts and/or the adhesive with minimal losses, for example a type of metal or alloy, such as steel, for example stainless steel.

FIG. 18 e illustrates a fifth exemplary step. Here, the ultrasonic radiation has been stopped to stop heating of the adhesive A. Consequently, the adhesive A starts to cool down, since no more heat is supplied, and since it is able to transfer heat energy to its colder surroundings. As a result, the adhesive is cured.

To summarize, FIG. 18 a-e and the associated text has explained how an adhesive activation arrangement AAA, can be used to apply/activate pressure, activate adhesive, cool adhesive, and cure adhesive. These steps may be performed manually, automatically, or as a combination of manually and automatically.

In other embodiments of the invention, an adhesive activation arrangement AAA may be configured to activate adhesive A to bond the adhesive A to a single footwear piece, e.g. a leather base layer LBL. Such a step may for example be performed prior to stacking an additional footwear piece, e.g. a leather attachment layer LAL, onto the adhesive A and bonding this additional footwear piece to the adhesive A by activating the adhesive A again. The step may for example be performed with the adhesive A surrounded by a leather base layer LBL on one side and a non-stick material such as Teflon on the other side. The non-stick material may then be removed from the adhesive prior to stacking an additional footwear piece.

FIG. 19 illustrates another automated footwear processing arrangement AFPA according to embodiments of the invention.

The illustrated automated footwear processing arrangement AFPA is composed of several steps, which may for example be carried out at a number of modules or workstations along a production line. In some embodiments of automated footwear processing arrangements AFPA, some modules are configured to carry out several of the illustrated steps. In some embodiments of automated footwear processing arrangements AFPA, some of the illustrated steps are excluded whereas in some embodiments of the invention, other steps not illustrated in the figure have been added. Some of the steps may for example be performed as exemplified in various embodiments throughout the description of the present invention, but the steps and arrangement/devices configured for performing the steps are not restricted to the presented examples. In the illustrated embodiment, a fixture FIX is used to facilitate part of the transportation of footwear parts between different steps. Generally, in embodiments of the invention, the transfer of footwear parts between the steps may for example also be performed as exemplified in any of the description of the present invention. In some embodiments, some of the individual steps may each be performed partly of fully automatically. And in some embodiments, some of the individual steps may each be performed partly of fully manually, within the scope of the claims.

In this embodiment, at least part of the automated footwear processing arrangement AFPA is aided by a visual detection system VDS. This system VDS may for example monitor at least some of the processes/steps of the automated footwear processing arrangement. In some embodiments, the visual detection system VDS is passive, in the sense that it does not supply an output upon which the automated footwear processing arrangement AFPA is operated. In some embodiments, the visual detection system is active, in the sense that it supplies an output which at least part of the automated footwear processing arrangement is operated upon, for example output based on data obtained by one or more cameras and/or one or more sensors. Cameras and sensors of the visual detection system may for example be distributed along key points of the automated footwear processing arrangement AFPA.

The processing arrangement AFPA receives leather L which is supplied to a leather cutting arrangement LCA which cuts the leather into footwear parts usable for producing footwear, for example one or more leather base layers LBL, one or more leather attachment layers LAL, and one or more other leather footwear parts LFP. These footwear parts LBL, LAL, LFP may then serve as input I for the automated footwear processing arrangement AFPA. In other embodiments, footwear parts LBL, LAL, LFP are provided to an automated footwear processing arrangement AFPA in a precut state, such that no leather cutting arrangement LCA is required as part of the automated footwear processing arrangement.

Any footwear parts LBL, LAL, LFP provided as input to the automated footwear processing arrangement AFPA are supplied to a pre-adhesion processing arrangement (PAPA). Here, any of the leather footwear parts LBL, LAL, LFP are prepared for further processing in the automated footwear processing arrangement AFPA. Particularly, any of the leather footwear parts may be cleaned to prepare for adding the adhesive, for example by removal of dust, fat, and other contamination. This may ensure improved bonding of leather parts LBL, LAL by the adhesive.

As a next step any footwear parts LBL, LAL, LFP is provided to a pick-and-place device PAPD which may pick up any of the parts and place them as required for further processing of the footwear/footwear parts. In the present embodiment, the pick-and-place device places at least some of the footwear parts on a fixture base layer of a fixture FIX. The fixture is supplied from a stack STA of fixtures, for example supplied from the stack STA by the pick-and-place device PAPD, of from a dedicated device for supplying a fixture form the stack STA of fixtures. In typical embodiments, some of the footwear parts are attached to the fixture base layer, for example be auxiliary adhesive, stitching, glue, clamps, or other attachment means. The process of attachment may for example be carried out by a dedicated attachment arrangement (not shown), for example an attachment arrangement capable of gluing or sewing. Any footwear parts to be processed which or not attached to the fixture base layer may for example lie on the fixture, for example on the fixture base layer or in a dedicated region of the fixture/frame of the fixture for un-attached footwear parts.

As a next step, the footwear parts and fixture are supplied to an adhesive application arrangement AAPA. Here, adhesive is applied to one or more footwear parts, for example one or more leather base layers LBL attached to the fixture FIX. Adhesive may for example be applied in the form of a web, a foil, or a fluid.

As a next step, the footwear parts and fixture are supplied to a three-way transfer 3WT. Here, the fixture and footwear parts may either be transferred on along the production line or transferred off the production line to a quality inspection system QIS. From the quality inspection system QIS, the footwear parts and fixture may be transferred back to the three-way transfer 3WT and onward on the production line. At the quality inspection system QIS, the footwear parts, any attachment to the fixture, and the applied adhesive may be inspected manually by a human operator HO, automatically by a camera or a sensor, or both manually and automatically.

After the three-way transfer, the footwear parts and fixture are supplied to an automatic stacking arrangement ASA. Here, footwear parts are stacked, for example such that at least one leather attachment layer LAL is stacked on at least one leather base layer LBL, with adhesive placed between any of the leather base layers LBL and leather attachment layers LAL.

As a next step, the footwear parts and fixture are again supplied to a three-way transfer 3WT associated with a quality inspection system QIS. As previously, the footwear parts, here particularly the stacking of footwear parts, may be inspected manually and/or automatically before the footwear parts and fixture is forwarded in the production line.

As a next step, the footwear parts and the fixture are supplied to an adhesive activation arrangement AAA. Here, the adhesive is activated to initiate bonding of any stacked leather base layers LBL and leather attachment layers LAL which have adhesive between them. The adhesive may for example be activated by heating, for example via resistive heating or ultrasonic transducers.

As a next step, the footwear parts and the fixture are supplied to an automatic pressure activation arrangement APA, automatic curing arrangement ACA, and/or an automatic cooling arrangement ACOA. In some embodiments, these three arrangements may for example be a single device. Preferably, the adhesive cures, for example by cooling passively, while footwear parts are fixed by pressure. This operation may be carried out by one or more arrangements APA, ACA, ACOA.

As a next step, the footwear parts and fixture are again supplied to a three-way transfer 3WT associated with a quality inspection system QIS. As previously, the footwear parts, here particularly the bonding of footwear parts, may be inspected manually and/or automatically before the footwear parts and fixture is forwarded in the production line.

As a next step, the footwear parts and fixture are supplied to an automatic stitching arrangement ASTA. Here sewing/stitching of footwear parts may be performed, at least partially automatically. The stitching/sewing may be performed as a supplement to the bonding of footwear parts using adhesive, or it may be performed to attach one or more other footwear parts to the footwear parts which have been bonded using adhesive. Such other footwear parts may have been supplied initially in the production line, e.g. a leather footwear part LFP from the leather cutting arrangement LCA, or it may have been supplied later in the production line (not shown). The automatic stitching arrangement ASA may be supplemented by other arrangements/devices, for example a pick-and-place device or an automatic stacking arrangement to prepare footwear parts for stitching.

As a next step, the footwear parts and fixture are supplied to an automatic cutting arrangement ACUA. Here, the footwear parts attached to the fixture are cut loose from the fixture by cutting the fixture base layer. The fixture base layer may for example be cut near the perimeter of the attached footwear parts. The part of the fixture base layer which is cut loose and which is attached to footwear parts may then serve as lining in the further processing of the footwear. However, note that embodiments of the invention are not limited to supplying footwear lining via the fixture base layer.

The frame FRA which have now been detached from the footwear parts are conveyed to a fixture processing module FPM, for example by means of one or more automated elevators, one or more conveyer belts, and/or manual movement. At the fixture processing module FPM, the frame FRA is attached to a new fixture base layer FLB to prepare a new fixture FIX which in turn is supplied to the stack STA of fixtures. Consequently, a continues supply of fixtures for automated footwear production is supplied by recycling the fixture frames FRA.

After the automatic cutting arrangement ACUA, the footwear parts are advanced to a three-dimensional phase 3D, in which the attachment of various footwear parts is performed while the footwear parts are in a three-dimensional configuration, as opposed to being in a two-dimensional configuration as was the case while footwear parts were being attached on the fixture. The three-dimensional phase 3D may for example include additional application, activation, and curing of adhesive or additional stitching, for example automated or manual stitching. In the present embodiment, the footwear parts are supplied to an automatic stitching arrangement ASTA, in which stitching is performed.

As a next step, the footwear parts are supplied to a sole attachment process SAP, in which a sole is attached to the footwear parts. In typical embodiments, the entire footwear upper, or at least most of the footwear upper, is assembled prior to this step, but note that embodiments of the invention are not restricted in this manner. The sole attachment process SAP may for example be based on injection molding/direct injection processing.

After a sole has been attached, a finalized piece of footwear FW has been produced as an output O of the automated footwear processing arrangement AFPA. The bonded leather base layer LBL and the leather attachment layer LAL has thus been integrated as part of a footwear FW.

Generally, embodiments of the automated footwear processing arrangement AFPA may include further supply and attachment of footwear parts required in the production of a complete piece of footwear FW. Generally, such further supply and attachment of footwear parts have been omitted to not obscure the description of the important steps and parts of the automated footwear processing arrangement AFPA. A skilled person may thus add and combine elements and steps of the illustrated automated footwear processing arrangement AFPA to ensure a complete piece of footwear, depending on the exact specifications of the footwear.

As shown in the illustration, one or more human operators HO may operate the automated footwear processing arrangement AFPA, but note that the invention limited in this respect. A human operator HO may for example operate one or more arrangements/devices which is part of the automated footwear processing arrangement AFPA. Further, a human operator may for example survey an inspect parts of the automated footwear processing arrangement AFPA.

FIG. 20 illustrates yet another automated footwear processing arrangement AFPA according to embodiments of the invention.

The invention has been exemplified above with the purpose of illustration rather than limitation with reference to specific examples of methods and systems for manufacturing footwear. Details such as a specific method and system structures have been provided in order to understand embodiments of the invention. Note that detailed descriptions of well-known systems, devices, circuits, and methods have been omitted so as to not obscure the description of the invention with unnecessary details. It should be understood that the invention is not limited to the particular examples described above and a person skilled in the art can also implement the invention in other embodiments without these specific details. As such, the invention may be designed and altered in a multitude of varieties within the scope of the invention as specified in the claims. For example, the presented automated footwear processing arrangements may be altered by rearranging, inserting and/or removing various workstations/modules/automated arrangements, for example to modify the adhesive-based footwear processing to any various purpose. 

1. A method of manufacturing at least a part of a footwear in an automatic footwear manufacturing line, the method comprising steps of: providing a first footwear part in a form of a leather base layer, providing a second footwear part in a form of a leather attachment layer, automatically stacking the leather base layer and the leather attachment layer against each other with an intermediate application of adhesive between them, automatically activating the adhesive, automatically forcing the leather base layer and the leather attachment layer against each other under a pressure with the adhesive between them, and curing the adhesive and thereby bonding the leather base layer and the leather attachment layer to each other thereby providing at least a part of a footwear upper. 2.-5. (canceled)
 6. The method of manufacturing at least the part of the footwear according to claim 1, wherein the step of automatically activating the adhesive is performed by heating the adhesive.
 7. The method of manufacturing at least the part of the footwear according to claim 1, wherein the step of automatically activating the adhesive is activated by subjecting the adhesive to UV-radiation (UV: Ultra violet radiation), IR (IR: Infrared radiation), Ultrasound or any combination thereof.
 8. A method according to claim 6, wherein at least one of the leather base layer or the leather attachment layer shrinks when heating the adhesive.
 9. A method according to claim 6, wherein the heating the adhesive is continued over a period of time and/or heated to a temperature by which at least one of the leather base layer or the leather attachment layer will shrink within a predetermined dimension range. 10.-12. (canceled)
 13. A method according to claim 6, wherein the adhesive is a foil and/or a web prior to bonding. 14.-19. (canceled)
 20. A method according to claim 1, wherein the adhesive is a non-reactive glue which is a hot-melt adhesive having a Tg (Tg: glass transition temperature) between 100 degrees Celsius and 200 degrees Celsius. 21.-22. (canceled)
 23. A method according to claim 1, wherein the leather base layer is formed of top grain leather, and wherein the top-grain side is facing towards the leather attachment layer. 24.-25. (canceled)
 26. A method according to claim 1, wherein the top-grain side of the leather attachment layer and/or the leather base layer is buffed.
 27. A method according to claim 1, wherein the leather attachment layer is formed of top-grain leather, having the top-grain side facing towards the exterior of the footwear. 28.-29. (canceled)
 30. A method according to claim 1, wherein the thickness of the leather attachment layer is between 0.3 mm to 2.0 mm. 31.-34. (canceled)
 35. A method according to claim 1, wherein the leather base layer is forming at least part of a leather vamp of the footwear.
 36. A method according to claim 1, wherein the leather attachment layer is forming at least part of a leather counter of a footwear, and/or wherein the leather attachment layer is forming part of a leather toe cap of a footwear. 37.-44. (canceled)
 45. A method according to claim 1, wherein the method is performed by in an automatic footwear processing arrangement (AFPA) having an input and an output, wherein the steps of providing the leather base layer and providing the leather attachment layer are performed in an automatic process transporting the leather base layer and the leather attachment layer from the input and automatically stacking these, one layer at least partially overlapping the other layer, wherein the step of automatically activating the adhesive is performed automatically by means of an automatic adhesive activation arrangement, and wherein the step of automatically forcing the leather base layer and the leather attachment layer against each other under the pressure with the adhesive between them is performed by an automatic pressure activation arrangement.
 46. (canceled)
 47. The method according to claim 45, wherein the method further comprises a step of curing the adhesive, performed subsequent to activation, via an automatic cooling arrangement. 48.-49. (canceled)
 50. The method according to claim 1, wherein the leather base layer and the leather attachment layer are automatically cleaned of dust prior to a reactivation of adhesive already present thereon, and/or, prior to the the step of automatically activating the adhesive via a pre-adhesion processing arrangement. 51.-55. (canceled)
 56. An automatic footwear processing arrangement (AFPA) defining an automatic footwear manufacturing line having an input and an output, the footwear manufacturing line including one or more stations configured for performing process steps, wherein the arrangement includes a station in the form of at least one automatically stacking arrangement stacking a leather base layer and a leather attachment layer obtained from the input (I), one layer at least partially overlapping the other layer and wherein the automatic stacking arrangement is cooperating with an associated automatic adhesive activation arrangement, the adhesive activation arrangement being arranged to automatically activate an adhesive between a mutually stacked leather base layer and leather attachment layer, the adhesive activation arrangement including or cooperating with an automatic pressure activation arrangement configured to force the leather base layer and the leather attachment layer against each other subject to at a pressure with the adhesive between them at the same time or subsequent to the activation of adhesive performed by the adhesive activation arrangement.
 57. The automatic footwear processing arrangement according to claim 56, wherein the one or more stations of the manufacturing line are interconnected with a transporting arrangement automatically configured for transporting footwear parts from one station to another station, and wherein the transportation of the footwear parts from the one station another station is controlled at least partly by a control arrangement so as to establish a manufacturing sequence for respective footwear items.
 58. The automatic footwear processing arrangement according to claim 57, wherein the control arrangement is monitoring movement of partially gathered footwear upper parts throughout a manufacturing sequence of a footwear upper. 59.-60. (canceled)
 61. The automatic footwear processing arrangement according to claim 56, wherein a process of curing the adhesive is performed subsequent to activation of the adhesive via an automatic cooling arrangement. 62.-68. (canceled)
 69. The automatic footwear processing arrangement according to claim 56, wherein the manufacturing line includes a subsequent automatic sole attachment arrangement for cementing a sole to a footwear upper.
 70. The automatic footwear processing arrangement according to claim 56, wherein the manufacturing line includes a subsequent automatic arrangement configured for direct injection of a sole to a footwear upper.
 71. (canceled) 